Engine chevrolet


Chevrolet Big-Block engine

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The Chevrolet "Big Block" is a term for a series of large displacement V8 engines that were developed and produced in the United States during the 1950s to the current day. As American automobiles grew in size and weight following the Second World War, the engines powering them had to keep pace. Chevrolet had introduced its popular small block V8 in 1955, but needed something larger to power its medium duty trucks and the heavier cars that were on the drawing board.

W-series (Mark I)

The first version of the "Big Block" V8 Chevrolet engine, known as the W-series, was introduced in 1958. Chevrolet designed this engine for use in passenger cars and light trucks. This engine had an overhead valve design with offset valves and uniquely scalloped rocker covers, giving it a distinctive appearance. The W-series was produced from 1958 to 1965, and had three displacement options:

  • 348 cubic inches (5.7 L), available from 1958 to 1961 in cars, and in light trucks through 1964;
  • 409 cubic inches (6.702 L), available from 1961 to 1965; and
  • 427 cubic inches (6.9973 L), available in 1962 and 1963.

The W-series engine was made of cast iron. The engine block had 4.84-inch (123 mm) bore centers, two-bolt main bearing caps, a "side oiling" lubrication system (the main oil gallery located low on the driver's side of the crankcase), with full-flow oil filter, and interchangeable cylinder heads. Heads used on the high performance 409 and 427 engines had larger ports and valves than those used on the 348 and the base 409 passenger car and truck engines, but externally were identical to the standard units. One minor difference between the 348 and 409/427 was the location of the engine oil dipstick: it was on the driver's side on the former and the passenger's side on the latter. No satisfactory explanation was ever offered for why this change was made. However, it did provide a fairly reliable way to differentiate between the smaller and larger versions of the engine.

As with the 265- and 283-cubic-inch "Small Block" engines, the W-series valve gear consisted of tubular steel push rods operating stud-mounted, stamped-steel rocker arms. The push rods also acted as conduits for oil flow to the valve gear. Due to the relatively low mass of the valve train, mechanical lifter versions of the W-series engine were capable of operating at speeds well beyond 6000 (RPM).

Unlike many of its contemporaries, the combustion chamber of the W-series engine was in the upper part of the cylinder, not the head, the head having only tiny recesses for the valves. This arrangement was achieved by combining a cylinder head deck that was not perpendicular to the bore with a crowned piston, which was a novel concept in American production engines of the day. As the piston approached top dead center, the angle of the crown combined with that of the head deck to form a wedge-shaped combustion chamber with a pronounced quench area. The spark plugs were inserted vertically into the quench area, which helped to produce a rapidly moving flame front for more complete combustion.

The theory behind this sort of arrangement is that maximum brake mean effective pressure (BMEP) is developed at relatively low engine speeds, resulting in an engine with a broad torque curve. With its relatively flat torque characteristics, the "W" engine was well-suited to propelling both the trucks and heavier cars that were in vogue in the USA at the time. The W-series was a physically massive engine when compared to the "Small Block" Chevrolet engine. It had a dry weight of approximately 665 pounds (302 kg), depending on the type of intake manifold and carburetion systems present.

348

The first iteration of the W-series engine was the 1958 "Turbo-Thrust" 348-cubic-inch (5.7 L), originally intended for use in Chevrolet trucks but also introduced in the larger, heavier 1958 passenger car line. Bore was 4.125 in (104.8 mm) and stroke was 3.25 in (82.6 mm), resulting in a substantially oversquare design. This engine was superseded by the 409-cubic-inch as Chevrolet's top performing engine in 1961 and went out of production for cars at the end of that year. It was produced through 1964 for use in large Chevrolet trucks.

With a four-barrel carburetor, the base Turbo-Thrust produced 250 hp (186 kW). A special "Tri-Power" triple-two-barrel version, called the "Super Turbo-Thrust", produced 280 hp (209 kW). A "Special Turbo-Thrust" further upped the power output to 305 hp (227 kW) with a single large four-barrel carburetor. Mechanical lifters and triple two-barrel carburetors brought the "Special Super Turbo-Thrust" up to 315 hp (235 kW). For 1959 and 1960, high-output versions of the top two engines were produced with 320 hp (239 kW) and 335 hp (250 kW) respectively. In 1961, power was again increased to 340 hp (254 kW) for the single four-barrel model, and 350 hp (261 kW) when equipped with triple two-barrels.

Versions First Year Last Year Model Name Features Power (Advertised Gross)
1958 1961 Turbo-Thrust 4 barrel 250 hp (190 kW)
1958 1961 Super Turbo-Thrust "Tri-Power" 3x2 barrel 280 hp (210 kW)
1958 1961 Special Turbo-Thrust 4 barrel 305 hp (227 kW)
1958 1960 Special Super Turbo-Thrust "Tri-Power" 3x2 barrel 315 hp (235 kW)
1959 1960 Special Turbo-Thrust 4 barrel 320 hp (240 kW)
1959 1961 Special Super Turbo-Thrust "Tri-Power" 3x2 barrel 335 hp (250 kW)
1960 1961 Special Turbo-Thrust 4 barrel 340 hp (250 kW)
1960 1961 Special Super Turbo-Thrust "Tri-Power" 3x2 barrel 350 hp (260 kW)

409

A 409-cubic-inch (6.7 L) version was Chevrolet's top regular production engine from 1961 to 1965, with a choice of single or dual four-barrel carburetors. Bore and stroke were both up from the 348 to 4.312 in (109.5 mm) by 3.50 in (88.9 mm). On December 17, 1960, the 409 engine was announced along with the Impala SS (Super Sport) model. The initial version of the engine produced 360 hp (268 kW), with a single four-barrel Carter AFB carburetor. The same engine was upped to 380 hp (283 kW) in 1962. A 409 hp (305 kW) version of this engine was also available, developing 1 hp per cubic inch with a dual four-barrel aluminum intake manifold and two Carter AFB carburetors. It had a forged steel crankshaft.[1] This dual-quad version was immortalized in the Beach Boys song titled "409".

In the 1963 model year, output reached 425 hp (317 kW) at 6200 rpm with the 2X4 setup, 11.25:1 compression and a solid lifter camshaft. The engine was available through mid-1965, when it was replaced by the 396-cubic-inch 375 hp (280 kW) Mark IV big-block engine. In addition, a 340 hp (254 kW) version of the 409 engine was available from 1963–1965, with a single four-barrel cast-iron intake mounting a Rochester 4GC square-bore carburetor, and a hydraulic-lifter camshaft.

427 (Z11)

A special 427-cubic-inch (7.0 L) version of the 409 engine was used in the 1963 Chevrolet Impala Sport Coupe, ordered under Chevrolet Regular Production Option (RPO) Z11.[2] This was a special package created for drag racers, as well as NASCAR,[3] and it consisted of a 427 cubic inch engine with aluminum body parts, and a cowl-induction air intake system. The aluminum body parts were fabricated in Flint, Michigan at the facility now known as GM Flint Metal Center.[4] Unlike the later, second-generation 427, it was based on the W-series 409 engine, but with a longer 3.65 in (93 mm) stroke. A high-rise, two-piece aluminum intake manifold and dual Carter AFB carburetors fed a 13.5:1 compression ratio to produce an under-rated 430 hp (320 kW) and 575 lb·ft (780 N·m). 50 RPO Z11 cars were produced at the Flint GM plant.

Extant GM Documents show 50 Z11 engines were built at the GM Tonawanda Engine plant for auto production, and 20 partial engines were made for replacement/over-the-counter use. Unfortunately, there is no evidence from GM that shows 57 cars were built.[clarification needed][citation needed]

Mark II

The so-called Mystery Motor, known internally as the Mark II or Mark IIS, is a race-only[5] engine produced for the 1963 season. Development began with a 409 cubic inches (6.7 L) version (Mark II) and ended with a 396 cubic inches (6.5 L) variant however only the 427 cubic inches (7.0 L) engine (Mark IIS) was ever raced. It gained its nickname due to the incredible speeds cars equipped with it attained during its debut being considerably faster than the well known W-series powered cars. The engine was first used in Mickey Thompson's Z-06 Corvettes at Daytona in the 1963 Daytona 250 Miles - American Challenge Cup,[6] then in Chevrolet's 1963 Daytona 500 record-setting stock cars. This "secret" engine was a unique design incorporating aspects of both the W-series and the mid-1965 introduced Mark IV [5] referred to in sales literature as the "Turbo-Jet V8".

Mark III

Packard V-8 tooling and production rights were considered for purchase by Chevrolet. Project did not proceed.[7]

Mark IV

The Mark IV differed from the W-series engine was in the placement of the valves and the shape of the combustion chambers. Gone was the chamber-in-block design of the W-series engine (which caused the power curve to drastically dip above 6500 RPM), and in its place was a more conventional wedge chamber in the cylinder head, which was now attached to a conventional 90 degree deck. The valves continued to use the displaced arrangement of the W-series engine, but were also inclined so that they would open away from the combustion chamber and cylinder walls, a design feature made possible by Chevrolet's stud mounted rocker arms. This alteration in valve placement resulted in a significant improvement in volumetric efficiency at high RPM and a substantial increase in power output at racing speeds. Owing to the appearance of the compound angularity of the valves, the automotive press dubbed the engine the "porcupine" design.

As part of the head redesign, the spark plugs were relocated so that they entered the combustion chamber at an angle relative to the cylinder centerline, rather than the straight-in relationship of the W-series engine. This too helped high RPM performance. Due to the new spark plug angle, the clearance provided by the distinctive scalloped valve covers of the W-series was no longer needed, and wide, rectangular covers were used.

In all forms (except the ZL-1 Can-Am model), the "rat motor", as it was later nicknamed (small-block engine being a "mouse motor"), was slightly heavier than the W-series model, with a dry weight of about 685 pounds (311 kg). Aside from the new cylinder head design and the reversion to a conventional 90 degree cylinder head deck angle, the Mark IV shared many dimensional and mechanical design features with the W-series engine. The cylinder block, although more substantial in all respects, used the same cylinder bore pitch of 4.84" with a larger 2.75" main bearing dimension, increased from the 2.50" of the older engine (in fact, the shorter-stroke 348 and 409 crankshafts could be installed with the use of "spacer bearings" without modifying the crankshaft). Like its predecessor, the Mark IV used crowned pistons, which were castings for conventional models and impact extruded (forged), solid skirt types in high performance applications.

Also retained from the W-series design were the race-proven Moraine M400 aluminum bearings first used in the 409, as well as the highly efficient "side oiling" lubrication system, which assured maximum oil flow to the main and connecting rod bearings at all times. Later blocks intended for performance use had the main oil gallery moved up to the cam bearing bore area and provided "priority main" oiling, improving the oil system even further. These features, along with the robust crankcase design, sturdy forged steel crankshaft and massive four-bolt main bearing caps used in the high performance versions, resulted in what many have considered to be the most rugged and reliable large displacement automotive V8 engine design of all time.[citation needed]

366

The 366 Big Block V-8 (6.0 L) gasoline engine was used only in Chevrolet medium duty trucks and in school buses. It had a bore of 3.935" (99.95mm) and a stroke of 3.760" (95.5mm). This engine was made from the 1960s until the mid-1990s. The 366 used 4 rings on the pistons, as it was designed from the very beginning as a truck engine. The 366 was only produced as a tall-deck engine, with a deck 0.400" taller than the 396, 402, and 454 short-deck Big Blocks.

396 and 402

The 396-cubic-inch (6.5 L) V8 was introduced in the 1965 Corvette as the L78 option and in the Z16 Chevelle as the L37 option. It had a bore of 4.094 in (104.0 mm) and a stroke of 3.760 in (95.5 mm),[8][9] and produced 375 hp (280 kW) and 410 lb·ft (560 N·m). The solid lifter version was capable of being operated in the upper 6000 rpm range, and when installed in the 1965 Corvette, was factory-rated at 425 horsepower.

Introduced in 1970, the 402-cubic-inch (6.6 L) was a 396-cubic-inch bored out by 0.030 in (0.76 mm). Despite the fact that it was 6 cubic inches (98 cc) larger, Chevrolet continued marketing it under the popular "396" label in the smaller cars while at the same time labeling it "Turbo-Jet 400" in the full-size cars. The 402 label was used in light pickup trucks.

Power rating(s) by year:

  • 1965: 375 hp (280 kW)/425 hp (317 kW)
  • 1966: 325 hp (242 kW)/350 hp (260 kW)/360 hp (270 kW)/375 hp (280 kW)
  • 1967: 325 hp (242 kW)/350 hp (260 kW)/375 hp (280 kW)
  • 1968: 325 hp (242 kW)/350 hp (260 kW)/375 hp (280 kW)
  • 1969: 265 hp (198 kW)(2bbl)/325 hp (242 kW)/350 hp (260 kW)/375 hp (280 kW)
  • 1970: 330 hp (250 kW)/350 hp (260 kW)/375 hp (280 kW)
  • 1971: 300 hp (220 kW) SAE gross; SAE net hp was 260 for dual exhaust and 206 for single exhaust
  • 1972: 240 hp (180 kW) SAE net for dual exhaust and 210 hp SAE net for single exhaust

Used in:

  • 1965 Chevrolet Corvette
  • 1965–1972 Chevrolet Chevelle
  • 1967–1972 Chevrolet Camaro
  • 1968–1970 Chevrolet Nova
  • 1970–1972 Chevrolet Monte Carlo, Chevrolet trucks
  • 1965–1972 Chevrolet Biscayne, Chevrolet Bel Air, Chevrolet Impala, Chevrolet Impala SS, Chevrolet Caprice

396 and 402 Production codes

396
  • L-34: produced 1966-9, 10.25:1 compression, Holley (Q-jet 1968-9) carburetor, hydraulic lifters, oval port closed chamber heads, forged steel crankshaft, and two-bolt main caps. It produced 350 to 360 hp (260 to 270 kW).[10]
  • L-35: produced 1965-9, had 10.25:1 compression, Q-jet carburetor, forged steel (1965-7) or nodular iron (1968-9) crankshaft, hydraulic lifters, oval port closed chamber heads, and two-bolt main caps. It produced 325 hp (242 kW).[10]
  • L-37: similar to L-78 except for having hydraulic lifters and slightly milder cam; 2-bolt main caps; designed specifically for the 1965 Z16 Chevelle
  • L-66: produced 1969, rare two-barrel carburetor, 9:1 compression, nodular iron crankshaft, hydraulic lifters, oval port closed chamber heads, and two-bolt main caps. It produced 265 hp (198 kW).[10]
  • L-78: produced 1965-9, had 800 cfm Holley carburetor, 11:1 compression, forged pop-top pistons, aluminum high-rise intake manifold, steel crankshaft, solid lifter cam (same as the L-72), rectangular ("square") port closed chamber heads, and four-bolt main caps. It produced 375 hp (280 kW) in mid-size cars, 425 hp (317 kW) in Corvettes.[10]
402
  • LS-3: produced 1970-2, 10.25:1 (1970) or 8.5:1 (1971) compression, hydraulic lifters, nodular iron crankshaft, and two-bolt main caps. It produced 330 hp (250 kW) (1970), 300 hp (220 kW) (1971), 210 or 240 hp (160 or 180 kW) (1972 net horsepower, single or dual exhaust).[10]
  • L-34: produced 1970. Same as 396 ci L-34.
  • L-78: produced 1970. Same as 396 ci.

427

L36 427 in a 1966 Chevrolet Corvette
L71 427 in a 1967 Chevrolet Corvette

The highly successful and versatile 427-cubic-inch (426.7 cuin) (7.0 L) version of the Mark IV engine was introduced in 1966 as a production engine option for full-sized Chevrolets and Corvettes. The bore was increased to 4.25 inches (108 mm), with power ratings varying widely depending on the application. There were smooth running versions with hydraulic lifters suitable for powering the family station wagon, as well as rough idling, high-revving solid lifter models usually applied to a minimally equipped, plain looking, two door Biscayne sedan fitted with the 425 horsepower (317 kW) version of the 427 - (RPO L72).

Perhaps the ultimate 427 for street applications was the 435 horsepower (324 kW) L71 version available in 1967 to 1969 Corvettes, and in the Italian Iso Grifo. This engine was identical to the 425 hp (317 kW) L72 427 (first introduced in 1966), but was fitted with three two-barrel carburetors (known as "Tri-Power"), in lieu of the L72's single four-barrel. Both engines used the same high lift, long duration, high overlap camshaft and large-port, cast-iron heads in order to maximize cylinder head airflow (and, hence, engine power) at elevated engine operating speeds. Consequently, the engines offered very similar performance and resulted in a car whose performance was described by one automotive journalist as "the ultimate in sheer neck-snapping overkill". Typical magazine road tests of the day yielded zero to 60 miles per hour (97 km/h) times under 6 seconds and quarter-miles in the mid 13 second/106 MPH range for both the L72 and L71.[citation needed]

In 2011, Super Chevy Magazine conducted a chassis dynamometer test of a well documented, production-line, stock but well-tuned L-72 "COPO" Camaro, and recorded a peak 287 SAE net HP (214 kW) at the wheels, demonstrating the substantial difference between 1960s-era SAE "gross" horsepower ratings versus post-1972 SAE "net".[11]

The RPO L89 was an L71 fitted with aluminum heads. While this option produced no power advantage, it did reduce engine (and hence, vehicle) weight by roughly 75 pounds (34 kg). This resulted in superior vehicle weight distribution for improved handling, although the difference in straight line performance was negligible.

The 1969 ZL1 version of the 427 engine was developed primarily for Can-Am racing, where it was very successful in cars like the McLaren M8B. The ZL1 had specifications nearly identical to the production L88 version of the 427, but featured an all-aluminum cylinder block in addition to aluminum cylinder heads, which dropped total engine weight into small-block Chevrolet territory (approx. 575 lb or 261 kg dressed).[citation needed] The engine was also fitted with the new open combustion chamber cylinder heads, a light weight aluminum water pump, a camshaft that was slightly "hotter" than the L88's, and a specially tuned aluminum intake manifold. Like the L88, the ZL1 required 103 octane (RON) (minimum) fuel, used an unshrouded radiator, and had poor low speed idle qualities - all of which made the two engines largely unsuitable for street use. (102 octane RON [Sunoco 260] represented the highest octane gasoline sold at common retail stations.)

As impressive as the ZL1 was in its day, actual engine dyno tests of a certified production line stock ZL1 revealed 376 SAE net HP (280 kW) with output swelling to 524 SAE gross HP (391 kW) with the help of optimal carb and ignition tuning, open long tube racing headers, and with no power-sapping engine accessories or air cleaner in place.[12] A second engine dyno test conducted on a second production line stock (but recently rebuilt and partially blueprinted) ZL1 revealed nearly identical figures for the various "gross" conditions.[13]

Period magazine tests of the ZL1 were quite rare due to the rarity of the engine itself. High Performance Cars tested a production line stock, but well tuned, example and recorded a 13.1 second/110 MPH quarter mile, which correlates quite well with the previously referenced 376 SAE Net HP figure. Super Stock and Drag Racing Magazine recorded an 11.62 second/122.15 MPH quarter mile in a ZL1 Camaro that was professionally tuned and driven by drag racing legend Dick Harrell, although that car was also equipped with open long-tube S&S equal-length headers, drag slicks and minor suspension modifications. Using Patrick Hale's Power/Speed formula, the 122.15 MPH trap speed indicated low 11-second ET (elapsed time) potential (e.g. with larger drag slicks) and suggested something on the order of 495 HP, "as installed", in that modified configuration. This large difference in power suggests that the OEM exhaust manifolds and exhaust system were highly restrictive in the ZL1 application, as was also the case with the similar L88.

The $4718 cost of the ZL1 option doubled the price of the 1969 Corvette, but resulted in a car with exceptional performance for its day. Just two production Corvettes (factory option at dealer) and 69 Camaros (non-dealer option from factory - COPO 9560) were built with the ZL1.

Chevrolet capitalized on the versatility of the 427 design by producing a wide variety of high performance, "over the counter" engine components as well as ready-to-race "replacement" engines in shipping crates. Some of the components were developed to enhance the engine's reliability during high RPM operation, possibly justifying the use of the description "heavy duty." However, most of these items were racing parts originally designed for Can-Am competition that found their way onto dealers' shelves, and were meant to boost the engine's power output.

Beginning in 1969, the highest performance 427 models were fitted with the new open (vs. closed) chamber cylinder heads, along with design improvements in crankshafts, connecting rods, and pistons, adopted from the Can-Am development program.

Chevrolet gave all 427 engines except the ZL1 a torque rating of 460 lb·ft (620 N·m).

First Year Last Year Engine Code Features Compression ratio Factory Gross Power Rating
1966 1969 L36 4-barrel 10.25:1 390 hp (290 kW)
1966 1969 L72 4-barrel + solid-lifters, more aggressive cam and high flow cylinder heads 11.00:1 425 hp (317 kW)[a]
1967 1969 L68 L36 with 3x2-barrel carbs. 10.25:1 400 hp (300 kW)
1967 1969 L71 L72 with 3X2 barrel carbs. 11.00:1 435 hp (324 kW)
1967 1969 L89 L71 + aluminum heads; RPO L89 also applied to L78 "375 HP" 396 engine with aluminum head option. 11.00:1 435 hp (324 kW)
1967 1969 L88 Racing-spec cam, high-flow aluminum heads (casting #s varied by model year) and some upgraded, competition-grade parts 12.50:1[b] 430 hp (320 kW)[c]
1969 1969 ZL1 Aluminum block with open chamber "3946074" aluminum heads; cam even "hotter" than L88's; upgraded parts similar to L88's 12.00:1 430 hp (320 kW)
1970 1977(?) ZLX L88-ZL1 hybrid; iron block with aluminum heads 12.25:1 430(?) hp (321 kW)

Notes:

  • 1966–1969 Chevrolet Biscayne
  • 1966–1969 Chevrolet Caprice
  • 1966–1969 Chevrolet Impala
  • 1966–1969 Chevrolet Corvette
  • 1968–1969 Chevrolet Camaro (most were dealer installed, but in 1969 both the L-72 and the ZL-1 were factory options)

427 Production codes

  • LS-1: produced 1969, 10.25:1 compression, Q-jet carburetor, oval port closed chamber heads, hydraulic lifters, nodular iron crankshaft, and two-bolt main caps. It produced 335 hp (250 kW).[14]
  • L-36: produced 1966-9, had 10.25:1 compression, Holley or Q-jet carburetor, nodular iron crankshaft, hydraulic lifters, oval port closed chamber heads, and two-bolt main caps. It produced 385 hp (287 kW) in 1967–68 full-size cars, 390 hp (290 kW) in 1969 full-size cars and Corvettes (by exhaust system).[14]
  • L-68: produced 1967-9, had 10.25:1 compression, Tri-Power, nodular iron crankshaft, hydraulic lifters, aluminum oval port closed chamber heads, and two-bolt main caps. It produced 400 hp (300 kW), and was used in Corvettes.[14]

454

The Big-Block was expanded again, for 1970, to 453.96 cubic inches (7.4 L), with a 4.250 in (108.0 mm) bore and 4 in (100 mm) stroke. The 1970 Chevrolet Corvette LS5 version of this engine was factory-rated at 390 hp (291 kW) and 500 lb·ft (680 N·m), and the LS6 engine was rated at 450 hp (340 kW). It has been suggested that the LS6 was substantially underrated from the factory, which was somewhat common practice by the American car makers, and that the engine actually produced well over 500 horsepower (370 kW) as delivered from the factory. Indeed, the AHRA ASA (Showroom Stock Automatic) Class record-holding Chevelle LS6 for the 1970 season posted a best of season trap speed of 106.76 mph (171.81 km/h),[15] which suggests something on the order of 350 "as installed" (SAE Net) HP for a 3,900 pounds (1,800 kg) car and driver combination. Indeed, Super Chevy Magazine conducted a chassis dyno test of a well-documented, well tuned, but production-line stock 1970 LS6 Chevelle and recorded 283 peak HP at the wheels[11] - a figure that lines up quite well with the previously referenced 350 SAE Net HP figure.

An even more powerful version, producing 465 hp (347 kW) and 610 lb·ft (830 N·m), of the 454, then dubbed LS7 (not to be confused with the modern, mid 2000s, 7-litre Chevrolet Corvette engine that powered the C6 Z06), was also developed. Several LS7 intake manifolds were individually produced and sold to the general public by a few Chevrolet dealers as optional performance parts. The LS7 was later offered as a crate engine from Chevrolet Performance with an officially rated power minimum of 500 Gross HP.

In 1971, the LS5 produced 365 hp (272 kW) and 550 lb·ft (750 N·m), and the LS6 option came in at 425 hp (317 kW) and 575 lb·ft (780 N·m). In 1972, only the LS5 remained, when SAE net power ratings and the move towards emission compliance resulted in a temporary output decline, due to lowered compression, to about 270 hp (200 kW) and 468 lb·ft (635 N·m). The 1973 LS4 produced 275 hp (205 kW) and 468 lb·ft (635 N·m), with 5 hp (3.7 kW) and 10 lb·ft (14 N·m) gone the following year. Hardened valve seats further increased reliability and helped allow these engines to last much longer than the earlier versions, even without the protection previously provided by leaded fuel. 1974 was the last year of the 454 in the Corvette, although the Chevelle offered it in the first half of the 1975 model year. It was also available in the full size Impala/Caprice through model year 1976.

General Motors introduced EFI in 1987, which was found on GM 2500 and 3500 trucks. The 454 EFI version was rated from 230 hp (170 kW) to 255 hp (190 kW) and from 385 lb·ft (522 N·m) to 405 lb·ft (549 N·m) of torque. GMC continued to use the 454 EFI until the new Vortec 7400 version arrived in 1996.

  • 1970–1976 Chevrolet Caprice
  • 1970–1975 Chevrolet Chevelle
  • 1970–1975 Chevrolet Monte Carlo
  • 1970–1975 Chevrolet El Camino
  • 1971–1972 GMC Sprint
  • 1970–1974 Chevrolet Corvette

Commercial applications

Mark IV engines saw extensive application in Chevrolet and GMC medium duty trucks, as well as in Blue Bird Corporation's All American and TC/2000 transit buses (the latter up until 1995, using a 427 with purpose-built carburetor). In addition to the 427, a 366-cubic-inch (6.0 L) version was produced for the commercial market. Both the 366 and 427 commercial versions were built with a raised-deck, four-bolt main bearing cap cylinder to accommodate an extra oil control ring on the pistons. Unfortunately, the raised deck design complicated the use of the block in racing applications, as standard intake manifolds required spacers for proper fit. Distributors with adjustable collars that allowed adjustments to the length of the distributor shaft also had to be used with 366 and 427 truck blocks.

Mark IV engines also found themselves widely used in power boats, a natural application for these robust power plants. Many of these engines were ordinary Chevrolet production models that were fitted with the necessary accessories and drive system to adapt them to marine propulsion. Mercury Marine, in particular, was a major user of the Mark IV in marine drives, and relabeled the engines with their corporate logo.

Generation V

General Motors changed from using the "Mark" designation to the "Generation" designation because Ford Motor Company owns the "Mark" naming rights as it was used on some Lincoln automobile models.[citation needed]

For 1991 General Motors made significant changes to the Big-Block resulting in the Generation V. The block received a one-piece rear seal and all blocks received 4-bolt mains. Additionally the main oil galley was moved from near the oil pan to near the camshaft. Also the valvetrain became non-adjustable and the previsions for a mechanical fuel pump were eliminated. Cast aluminum rocker covers were fitted in place of stamped steel covers.[16]

454

The 454 cubic inch engine continued to be used in production vehicles.

502

The Chevrolet 502 V8

The 502—with a 501.28-cubic-inch (8.2 L) total displacement—had a bore of 4.466", with a stroke of 4.00", and a cast iron 4-bolt main block. GM offered it in their Performance Parts catalog, available as multiple crate motors with horsepower ratings from 338 hp (252 kW) to 600 hp (447 kW), and torque of 470 lb·ft (637 N·m) to 567 lb·ft (769 N·m) in "Base" and "Deluxe" packages.[17] The "Ram Jet 502",[18] the 496 hp (370 kW) / 565 lb·ft (766 N·m) crate motor, was offered with fuel injection, and came as a turn key setup which included all the wiring and electronics needed to operate in any vehicle. It was also used in marine applications.

572

General Motors began offering a newly developed 572-cubic-inch (9.4 L) in 1998[19] to the aftermarket via its GM Performance Parts division. This engine has a bore of 4.560" and a stroke of 4.375". This is a 620 hp (462 kW) / 650 lb·ft (881 N·m) version, designated ZZ620/620 Deluxe, capable of running on 92 octane pump gasoline for street applications.[20] Another version of the same engine is available as a high compression variant, codenamed ZZ572/720R Deluxe, generating a minimum of 720 hp on high-octane i.e. race-gas.[21]

Generation VI

L29

The Vortec 7400 L29 7.4 L (454 cu in) V8 was a truck version of the Chevrolet Big-Block engine. Introduced in 1996, it was produced for five years, until replaced by the Vortec 8100. Although introduced as the Vortec 7400 in 1996, it was basically a 454 Big-Block with a hydraulic roller cam, parts more suitable for use in light duty trucks, and more advanced technology. The engine had MPFI (multi-port fuel injection), which gave slightly more power and better fuel economy, and 2 valves per cylinder. The engine had a 107.95mm (4.250 inch) bore, 101.6 millimetres (4.0 inches) stroke, and produced 290 hp (216 kW) at 4000 rpm and 410 lb·ft (556 N·m) at 3200 rpm.

L29 Applications:

  • 1996–2000 Chevrolet/GMC C/K GMT-400 platform trucks 2500 and 3500
  • 1996–1999 Chevrolet Suburban 2500/GMC Suburban 2500 (option)
  • 1996–2000 Chevrolet Express 3/4 or 1 ton

L21

The Vortec 7400 L21 was a commercial version of the Chevrolet Big-Block engine used in the medium duty truck platform. Its design shared much with the L29 454, but with the addition of forged pistons and crankshaft, and coil near plug ignition. It had slightly reduced power compared to the L29 454 and used a different PCM. The L21 was paired with the early 4 speed Allison automatic transmission or manual transmission, depending on the application.

L21 Applications:

  • 1998–2001 Chevrolet Kodiak/GMC TopKick/Isuzu H-Series 4500 5500
  • 1998–2001 Kodiak/Topkick
  • 1998–2001 P12 HD Motorhome Chassis. The Workhorse W-20 is a clone of the P12 Chassis.

Generation VII

L18

The Vortec 8100 L18 was a V8 truck engine. It was a redesigned Chevrolet Big-Block engine and was introduced with the 2001 full-size pickup trucks. It is an all-iron engine (block and heads) with two valves per cylinder. It retained the same bore diameter as the old 7.4 L Big-Blocks, but the stroke was upped by 9.4 mm (0.37 in) to reach 8.1L (496cuin), for a total of 107.95 mm (4.25 in) bore and 111 mm (4.37 in) stroke. Power output ranged from 340 hp (254 kW) to 550 hp (410 kW),[citation needed] and torque from 455 lb·ft (617 N·m) to 690 lb·ft (936 N·m).

Other important differences between the Vortec 8100 and older Big Blocks include a changed firing order (1-8-7-2-6-5-4-3), a new 18-bolt head bolt pattern, longer connecting rods, different symmetrical intake ports, different oil pan rails and the use of metric threads throughout the engine. The fuel-injection system for the Vortec 8100 is nearly identical to that used on Gen III engines, right down to the fuel and spark tables in the ECU.[22]

Vortec 8100s were built at GM's Tonawanda Engine plant. The last L18 was manufactured in December 2009.

L18 Applications:

GM sold the Vortec 8100 to Workhorse (now a division of Navistar), making it one of the most popular engine choices in gas powered Class A motorhomes during the first decade of this century. GM stopped installing Big Block V8s in the Silverado HD trucks when the GMT-800 series was discontinued in 2007.

  • Chevrolet Silverado/GMC Sierra 2500HD & 3500HD (option)
  • Chevrolet Suburban/GMC Yukon XL 2500 (option)
  • Chevrolet Express 3/4 or 1 ton
  • Chevrolet Avalanche 2500 (std on GMT800 2500)
  • Chevrolet Kodiak
  • Workhorse Class A motorhomes.
  • T-98 Kombat armored vehicles.
  • U-Haul's 26-foot (7.9 m) truck.
  • Malibu Boats, e.g. Wakesetter.[23]
  • MasterCraft Boats

Aftermarket

Many custom engine builders across the United States, as well as a large variety of aftermarket components manufactured for the Big Block family, make it possible to build a complete Big Block engine that contains no Chevrolet components. Blocks made of both iron and aluminum alloys, for many different purposes—e.g. street-use, racing, etc.—are available in stock or modified configurations, as well as with increased deck height to allow for a longer stroke or more favorable rod length ratios, depending on intent, providing the ability to make engines with capacities of 632-cubic-inch (10.4 L),[24] 798-cubic-inch (13.1 L),[25] and as large as 1,005.8-cubic-inch (16.5 L).[26]

See also

From the 1950s through the 1970s, each GM division had its own V8 engine family. Many were shared with other divisions, but each design is most closely associated with its own division:

  • Buick V8 engine
  • Cadillac V8 engine
  • Chevrolet Small-Block engine
  • GMC V8 engine
  • Oldsmobile V8 engine
  • Pontiac V8 engine
  • Holden V8 engine

GM later standardized on the later generations of the Chevrolet design:

  • GM LT engine—Generation II small-block
  • GM LS engine—Generation III/IV small-block
  • List of GM engines

Competitors' equivalent offerings:

  • Chrysler B engine - wedge
  • Chrysler Hemi engine - hemi
  • Ford 385 engine - big block
  • Ford FE engine - medium block

Footnotes

  1. ^ Chevrolet actually advertised this engine as 450 hp (340 kW) for a short period of time. There is speculation over whether this engine actually put out 450 Gross HP, or if this was a marketing oversight that was later corrected.
  2. ^ L88 had a 12.5:1 compression ratio with closed chamber heads except during the last half of 1969, when it had open chambered heads that yielded 12.0:1
  3. ^ L88 was rated for 430 hp (320 kW) at 5200 rpm. With stock exhaust manifolds and operation in the 6,800 rpm range, it was generally accepted that the engine was capable of producing in excess of 500 Gross HP with free-flowing (open) long tube headers.

Citations

  1. ^ the Auto Editors of Consumer Guide (2008-04-24). "HowStuffWorks "Chevy 409-cid V-8 Engine Overview"". Auto.howstuffworks.com. Retrieved 2012-05-31. 
  2. ^ "[Chevrolet's] 1963 Z-11 427 Impala". 348-409.com. 2015. Retrieved April 2, 2015. 
  3. ^ RK Motors Charlotte (June 28, 2013). 132954 / 1963 Chevrolet Impala SS. YouTube. Retrieved April 7, 2016. 
  4. ^ "GM U.S. Facilities - Flint Metal Center - Plant Summary". GM Global Operations. 2005. Archived from the original on November 6, 2006. Retrieved April 2, 2015. 
  5. ^ a b "Inside the Mark II Mystery Motor". Hot Rod Engine Tech. Retrieved 6 June 2017. 
  6. ^ Gillogy, Brandan (10 September 2015). "Mickey Thompson Z06 Mystery Motor Stingray". Hot Rod Network. Retrieved 16 September 2016. 
  7. ^ "Did Chevy consider Packard V8 BB Design?". Packard Info Forum. Retrieved 11 June 2017. 
  8. ^ McGann, John (October 1, 2010). "396 Big Block Chevy Stroker Build - Stock-Appearing Stroker 396". Hot Rod Network. Retrieved January 20, 2015. 
  9. ^ Mann, Dave (September 26, 2013). "Big block Chevy engines". Roadsters.com. Retrieved January 20, 2015. 
  10. ^ a b c d e Guide to Muscle Cars: 62. February 1987.  Missing or empty |title= (help)
  11. ^ a b Hill, Patrick (February 1, 2011). "Chevrolet Muscle Car Dyno Wars". Superchevy.com. Super Chevy Magazine. Retrieved November 1, 2014. 
  12. ^ Glowacki, Bill; et al. (2014). "COPO 427: The Relentless Pursuit of Acceleration". CRG Research Report. Camaro Research Group. Retrieved November 1, 2014. 
  13. ^ "2nd ZL1 DYNO TEST". Musclecar Enthusiast: 20–24. Archived from the original on June 4, 2011. Retrieved April 2, 2015. 
  14. ^ a b c Guide to Muscle Cars: 63. February 1987.  Missing or empty |title= (help)
  15. ^ "1970 Chevelle 454 LS6". Retrieved November 1, 2014. 
  16. ^ "The Novak Guide to the Chevrolet Big Block V8 Engine". Retrieved 13 June 2017. 
  17. ^ "2008 Crate Engine Catalog" (PDF). p. 25. Archived from the original (PDF) on 2009-02-06. Retrieved April 3, 2015. 
  18. ^ "Ram Jet 502: Outrageous Style and Fuel-Injected Drivability – All with Big-Block Power". Chevrolet. Retrieved April 19, 2015. 
  19. ^ Freiburger, David (June 2006). Hot Rod Horsepower Handbook: Big-Block Chevy. Motorbooks. p. 72. ISBN 9780760327838. Archived from the original on 2013-06-21. Retrieved April 19, 2015. 
  20. ^ "ZZ 572/620 Deluxe: Our Most Powerful Big-Block Street Engine". Chevrolet. Retrieved April 19, 2015. 
  21. ^ "ZZ 572/720R: Our Baddest, Most Powerful Big-Block Engine is Ready for the Strip". Chevrolet. Retrieved April 19, 2015. 
  22. ^ "Automotive Repair Questions - TPI - Car Craft Magazine". Carcraft.com. Retrieved 2012-01-25. 
  23. ^ wildbill; et al. (July 2011). "Why did Mailbu stop using the 8100 Vortec". The Malibu Crew. Retrieved June 14, 2015. 
  24. ^ "632 Big Block Chevy UltraStreet Big Dawg Twisted SR20 Crate Engine". Shafiroff Racing. Retrieved April 19, 2015. 
  25. ^ 798 cubic inch big block chevy: first start up of the 798 cid engine in the 66 chevelle. dragTimes (Video). Retrieved April 19, 2015 – via YouTube. 
  26. ^ "1005.8ci Godfather Big Block Engine – The Biggest Rat Ever!". HotRod. Retrieved February 16, 2017. 

Further reading

  • Peter C Sessler (1999). Ultimate American V8 Engine Data Book. MotorBooks/MBI Publishing Company. ISBN 0-7603-0489-0. 

en.wikipedia.org

Chevrolet straight-6 engine

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The Chevrolet inline 6 otto engine was Chevrolet's sole engine from 1929 (when it replaced their first 4-cylinder engine, the 171-cubic-inch four), through 1954, and was the base engine starting in 1955 when they added the small block V8 to the lineup. It had finally been completely phased out by 1990 in North America, but in Brazil, GM held on to their fuel-injected version through the 1998 model year. It was replaced by more recently developed V6 and four-cylinder engines. Many popular cars and trucks, including the Chevrolet Camaro, Chevrolet Impala, and Chevrolet Suburban used the inline 6 as the base engine. Chevrolet did not offer another inline 6 until the 2002 General Motors Atlas engine's debut in the Chevrolet TrailBlazer.

1st Generation (1929 Stovebolt Era)

The first mass-produced GM inline 6 was introduced in 1929 on Chevrolet cars and trucks, replacing the company's first inline-4. Richard Grant (Chevrolet marketing executive) insisted that the new design boast overhead valves. Chevrolet had long been known for its "valve-in-head" four-cylinder engines. William S. Knudsen's cast-iron wonder was produced through 1936.

194

It was 193.9 cubic inches (3.2 L) in size and produced 50 hp (37 kW). This engine used a forged steel crankshaft with three bearings and cast-iron pistons. Bore and stroke was 3.3125 in (84.14 mm) by 3.75 in (95.25 mm). The 194 was shared with Chevrolet and GMC trucks for 1935 and 1936.

A balanced crankshaft was introduced for 1932, while a higher (5.2:1) compression ratio upped output to 60 hp (45 kW). Applications:

  • 1929 Chevrolet Series AC International (Only $10 more than 1928s four-cylinder)
  • 1930 Chevrolet Series AD Universal

This engine was used in all Chevrolet passenger cars 1929-1933, and the 1934 "Standard" models.

181

A 181-cubic-inch (3.0 L) (3.3125 x 3.5) version was used by Chevrolet and GMC trucks in 1935 and 1936.

207

1933 Chevrolet L6 engine

206.8-cubic-inch (3.4 L) (3.3125 x 4) variant was used by Chevrolet and GMC trucks in 1934, 1935, and 1936. The 1934 Chevrolet "Master Deluxe" series used this engine, as did all 1935-1935 Chevrolet passenger cars. This newly revised engine put out 80 hp (60 kW).

Oldsmobile's flathead straight six in Chevrolet and GMC trucks

In 1935 and 1936, GMC and Chevrolet used an Oldsmobile 213 L-head engine. For 1937 and 1938, they used Oldsmobile's 230 L-head engine.

Second generation

The next-generation Chevrolet inline 6 was introduced in 1937 and phased out in 1963 in the US, and 1964 in Brazil. It is often known as the "Blue Flame" engine, although that name was only officially applied beginning in 1953, and then only for one certain model of the engine.[1]

This engine had a 216.48-cubic-inch (3.5 L) displacement with a 3.500” (88.90 mm) bore and a 3.750” (95.25 mm) stroke. A four-bearing crankshaft was added, along with 6.5:1 compression pistons, for 85 hp (63 kW). A new cylinder head in 1941 increased output to 90 hp (67 kW), and 6.6:1 compression gave the 1949 model 92 hp (69 kW). This generation did not use a fully pressurized oiling system. The connecting rods were oiled using an "oil trough" built into the oil pan that had spray nozzles that squirted a stream of oil at the connecting rods (which were equipped with "dippers"), thus supplying oil to the rod bearings.

Rod bearings were made of babbitt cast integral with the rod. The bearing was adjustable for wear by removing copper shims placed between the rod cap and connecting rod. In this way specified oil clearance could be maintained. If the crankshaft were to be turned undersized, or if the bearing was damaged or worn out, rod and bearing were replaced as a unit, typically at the dealership.[citation needed]

This engine was also used in GM's British Bedford truck. In the late 1930s rival Austin decided to get into the 2-3 ton truck ("lorry") market and in a crash program based the design—one might say shamelessly copied[citation needed] - on the basic architecture of this "Stove Bolt" engine, except that they added detachable shell main and con-rod bearings and pressurized lubrication. That Austin engine, in six-cylinder form, post war, went on to power cars such as the Austin Sheerline and Princess, and the Jensen Interceptor and 541. Austin also lopped off two cylinders and in that form various versions, with various capacities, powered cars such as the Austin 16, A70 Hampshire and Hereford, A90 Atlantic, the Austin-Healey 100-4 and the Austin Gipsy, plus a generation of commercial vans, plus the iconic London black taxi (FX3 and FX4).

235

1953 Corvette Blue Flame

In 1941, a 235.49 cu in (3,859 cubic centimetres) version of the 216 engine was introduced for use in large trucks. Both the bore (3.5625” or 90.49 mm) and stroke (3.9375” or 100.01 mm) were increased over the 216. This engine also had an oil "dipper system" as described above, in reference to the oiling system, as in the 216.

This 235-cubic-inch (3.9 L) version was added to cars in 1950 to complement the new Powerglide automatic transmission, and 3.55:1 rear differential. Hydraulic lifters were used in the Powerglide 235 and a fully pressurized lubrication system was introduced in 1953, but only in cars ordered with the "Powerglide" transmission. The 216-cubic-inch (3.5 L) continued to be standard powerplant for cars with the three-speed manual transmission until 1954, when the 235-cubic-inch (3.9 L) became the standard powerplant on all Chevrolet passenger cars. Two versions were used in 1953 cars - a solid-lifter version called the Thrift-King, with 123 hp (92 kW) for standard transmissions, and the hydraulic-lifter 136 hp (101 kW) version (the Blue-Flame) for Powerglide use. The "Blue Flame" moniker had been used in Chevrolet advertising since 1934. A blue rather than yellow flame within the cylinder meant that perfect combustion was achieved, promised GM's ad men.[1]

The major limitation for performance on the 235 was the design of the intake and exhaust ports. Unlike more modern straight sixes, the 235 had siamesed ports, with three intake ports and four exhaust ports. This meant the adjacent cylinders 2 and 3 and cylinders 4 and 5 shared a single exhaust port between them, whereas cylinders 1 and 6 had their own exhaust ports. Secondly, since there were only three intake ports, each port was divided between a pair of adjacent cylinders: 1 and 2, 3 and 4, and 5 and 6 shared an intake port. The design of the intake manifold also favored the middle port (and therefore the middle two cylinders). This ultimately caused the four end cylinders to receive less mixture, resulting in an unequal and unbalanced work load between the six cylinders.

From 1954 to 1963, the high-pressure 235 engine with mechanical valve lifters was used in some trucks. From 1956 to 1962, all 235 engines used in cars had hydraulic lifters.

The original 1953 Corvette engine was the high-pressure 235 engine equipped with mechanical lifters. A 150 hp 235 engine was used in the 1954 Corvette and into 1955 (until they were all sold). The Corvette 235 was equipped with the same slightly higher-lift camshaft as used in the 261 truck engine and used triple side draft, single barrel, Carter Model YH carburetors mated to a PowerGlide transmission and dual exhaust manifold.

The Chevrolet 235-cubic-inch is known as one of the great Chevrolet engines, noted for its power and durability. It was gradually replaced by the third generation 230, beginning in 1962.

Canadian production GMC trucks used the 216 and 235 Chevrolet straight six engines as their base light duty truck powerplant in the late 1940s and early 1950s in Canada, not USA. The 216 was used from 1947 to 1953, and the 235 was used in 1954 light duty trucks only. Medium duty GMC trucks used US built GMC engines in the 248, 270, and up sizes prior to 1954.

Toyota built the similar 236-cubic-inch Toyota F engine from 1955 to 1974, although it used a modified head from the previous "stovebolt" engine.

261

In 1954, a 260.9-cubic-inch (4.3 L) truck engine was introduced as an optional Jobmaster engine for heavy-duty trucks. This engine was very similar to the 235 engine, except for a different block casting with a larger piston bore of 3.750” or 95.25 mm, two extra coolant holes (in the block and head) between three paired (siamesed) cylinders, and a slightly higher lift camshaft. This engine was offered as a step up from the 235 starting in 1954. It was offered in parallel with the GMC V6 engine in 1960 until 1963, when it was discontinued. The 261 USA truck engine had mechanical lifters and was available from 1954 to 1962.

The 235 and 261 truck engines were also used by GMC Truck of Canada (GMC truck 6-cylinder engines were also used in Canada). The 1955–1962 Canadian full-size Pontiac car had a standard 261-cubic-inch engine that had hydraulic lifters. This engine was not sold in the USA, but was very similar to the USA truck 261.

The 261 engines were also used in light trucks and the Chevrolet Veraneio from 1958 to 1979 in Brazil.

Third generation

Chevrolet's third-generation inline six was introduced in 1962 (two years after rival Chrysler introduced its Slant Six as a replacement for the long-obsolete Chrysler 90hp 230 cubic-inch flat-head six-cylinder engine), and was produced through 1988. Although the exterior dimensions were similar to previous Chevrolet OHV inline six-cylinders, this generation was lighter and had a different cast-in bell housing pattern it shares with all Chevrolet engines designed and produced after 1954, including the modern LS-series "small-block" Chevy V8s and the 8.1L "big-block" Chevy V8s. The first three third-generation engines with 230, 250 and 292 cubic inches share the 3.875" bore with the first three small-block V8 engines, which are the 265, 283 and 307 cubic inch V8s.

Some of the many third-generation engines have bores and/or strokes in common with other Chevrolet engines, while others have bores and/or strokes unique to themselves. Since Chevrolet produced its "first-generation" small-block V8s and third-generation inline 6-cylinders during a period of several decades and for many General Motors and outside OEM manufacturers in several different factories, most situations where the V8s share parts or dimensions with the 6-cylinders are happenstance or coincidence rather than the result of a concerted effort to maximize commonality, which wasn't confined to the 6-cylinders and small-block V8s. There are certain parts and dimensions some 6-cylinder engines share with big-block Chevy V8s, which is another case of convenience and coincidence rather than design.

By the time the third-generation 6-cylinders were being designed and developed, Chevrolet was the most popular brand of vehicles in the world, and sales and production of vehicles and engines were into the millions of units per year with increasing markets for Chevrolet engines both within General Motors and outside the company in the industrial/commercia/agricultural/military/transportation markets both in the U.S. and worldwide.

As Chevrolet's first engine family produced with both Chevrolet and General Motors use and applications in mind and for widespread marketing and sales to other OEMs who purchased engines for applications ranging from marine propulsion to powering agricultural machinery to use by other motor vehicle manufacturers in their own vehicles, Chevrolet engineers concentrated on making the engines as interchangeable with the small-block and big-block V8s as possible without wasting time, money and personnel resources building the new 6-cylinders with as many off-the-shelf V8 parts as possible.

The huge success of Chevrolet since the introduction of the small-block V8s for the model year and the W-series big-block introduction in the 1958 model year had resulted in a huge increase in engine production and Chevrolet engineers had subsequently recognized mistakes or weaknesses in the V8 engines, had improved the engines and had developed new processes and technologies that in some ways made the third-generation 6-cylinders descendants of the V8s and in others made them ancestors of improved V8 engines when even more was learned from the 6-cylinders and was then applied to existing and new V8 engines.

There was no need to pinch pennies and spend dollars trying to save dimes by making a V8 part fit a 6-cylinder or vice versa when a better part designed and produced specifically for either family resulted in a better finished product and the larger initial investment was repaid many times over as a result. General Motors in general and Chevrolet Division in particular had learned much from Ford's fall from dominance and a near monopoly of the U.S. auto industry, which primarily resulted from reluctance to change and resistance to outside opinions and criticisms from potential, existing and former customers who generally supported Henry Ford and his company and products, but felt that Ford produced the products it thought best for Ford while paying little attention to what was wanted and needed by those who paid the bills with their purchases of Ford products. General Motors and Chevrolet were determined to be the antithesis of Ford Motor Company and its perceived "take it or leave it" attitude.

A 153 cubic-inch inline 4-cylinder engine with bore and stroke identical to the 230 cubic-inch inline 6-cylinder was produced and many internal parts were common to both engines.

There were other major differences between the third-generation 6-cylinder/153 4-cylinder and previous Chevrolet inline OHV engines.

The Gen-3 crankshafts had 7 main bearings (increased from 4). . The 230 reduced stroke to 3.25" from the comparable 235 design's 3.9375". The combustion chamber changed to a conventional wedge design much like the V8. The harmonic damper gained cast-in pulley provisions. Air-conditioned vehicles had a stamped-steel pulley bolted up front. Stamped and stud-mounted rocker arms were introduced, similar to the V8, and the ratio was close to the one used in the Chevrolet GEN IV big block (1.75:1 ratio) rather than the shaft-mounted earlier rockers at 1.477:1. The HEI (High Energy Ignition) system with an electronic pickup replacing the points and the coil locate in the distributor cap became standard equipment for the 6-cylinder engines concurrent with its use in the small-block and big-block V8s.

Two variants of the third generation six were produced - the 194/230/250 cid short deck (used in passenger cars, light trucks, and vans), and the tall deck 292 (used with some light trucks, vans, and commercial vehicles, which retained the dimensions of the previous generation "Stovebolt" six-cylinders, which were so-named due ).

The first use was in the newly introduced 1962 Chevy II; the following year, Chevrolet passenger cars adopted it (alongside Checker Marathons since 1965) and used this powerplant until 1977 (1979 for Camaros, Novas, and full size Chevrolets). Chevrolet/GMC trucks, which previously used the stovebolts (235 and 261), also used some members (with the tall deck 292 with both the light duty and medium duty trucks, C40-C60) of this family from 1963 through 1984 (short deck motors), as did Pontiac in 1964 and 1965. A 153-cubic-inch inline-4 version of this engine was offered in the Chevy II/Nova line through the 1970 model year. After several years of steadily declining sales (just 3,900 units in the 1972 model year),[2] the straight six was dropped from Chevrolet's full-sized cars for 1973, for the first time since 1928; it would be restored in 1977.[2] Sidenote: the base six cost about US$334 less than a V8, and weighed some 188 lb (85 kg) less.[2]

By the mid-1970s, the compact V-design (e.g. Buick 231) led to inline six engines being phased out in passenger cars, but they continued to be installed in trucks and vans until 1988.

Overseas, the third generation of the inline six was mass-produced in Brazil. It was used in the Chevrolet Opala from 1969 (230) to 1992 (250). It was already used in light trucks as the A and Chevrolet Veraneio. The Brazilian version of the GMT400 – the Brazilian Chevrolet Silverado – is powered with a 4.1 instead of the Vortec 4300 V6. Brazilian produced sixes manufactured to the 2001 model year gained multipoint fuel injection unlike the USA-manufactured sixes which retained the Rochester Monojet one barrel carburetor. These inline sixes and their four-cylinder siblings were converted for marine usage by Mercruiser and Volvo Penta, and also used in stationary applications (such as power generation) and in Clark forklifts.[citation needed][dubious – discuss] Aftermarket port fuel injection and re-engineered cylinder heads have been the norm although parts for the six e.g. aftermarket intake manifolds (from a three carburetor setup or a single 4-barrel carburetor), exhaust headers, and/or hybrid cylinder heads based on the small block are costlier than the Small Block Chevrolet unlike the rival AMC inline six (which has a cult following with Jeep enthusiasts, especially with the 4.0L).

194

The 194 (3,185 cc or 3.2 L) was shared between Chevrolet and GMC trucks.

Applications:

  • 1962–1967 Chevy II
  • 1962–1974 Chevrolet 400 (Argentina)
  • 1962–1974 Chevrolet 400 Special (Argentina)
  • (Circa 1965-66) Holden HD (South Africa)[3]
  • (Circa 1966-67) Holden HR (South Africa)[4]
  • 1968–1974 Chevrolet 400 Rally Sport (Argentina)
  • 1964–1967 Chevrolet Chevelle
  • 1965–1966 Studebaker Commander, Daytona ('66 only), Cruiser and Wagonaire (built by McKinnon Industries in Canada)
  • 1973-1978 Chevrolet 4100 (South Africa)

215

Pontiac's 215 (1964–1965) was a smaller bore (3.75") version of the 230 cu in (3.8 L) Chevrolet straight-6 engine.

230

The 230 (3,768 cc or 3.8 L) replaced the long-stroke, second generation 235 cu in (3.9 L) version. Bore and stroke are 3.875 in (98.43 mm) and 3.25 in (82.55 mm) respectively. It was also used by Chevrolet and GMC trucks, primarily for the half-tons. It produced 140 hp (100 kW). The 230 had a firing order of 1-5-3-6-2-4 rotating clockwise. It was also built in Latin America and was in production in South Africa until at least 1982, where it powered a multitude of different cars. A four-cylinder version of this engine was also built, as the Chevrolet "153" engine.

This engine was used on the following vehicles:

  • 1973-1979 Chevrolet 3800 (South Africa)
  • 1963–1969 Chevrolet Chevelle/Malibu
  • 1965–1968 Checker Marathon
  • 1965 Chevrolet El Camino
  • 1964–1970 Chevrolet Chevy II / Nova
  • 1966 Studebaker Commander, Wagonaire, Daytona and Cruiser
  • (Circa 1966-67) Holden HR (South Africa) [4]
  • 1967 Chevrolet Camaro
  • 1962–1974 Chevrolet 400 Special (Argentina)
  • 1964–1974 Chevrolet 400 Super (Argentina)
  • 1972–1974 Chevrolet 400 Rally Sport (Argentina)
  • 1969 Chevrolet Camaro
  • 1978-1982 Chevrolet Commodore (South Africa)[5]
  • 1968–1971 Chevrolet Opala (Brazil)
  • 1963–1967 Pontiac (fullsize, Canada)
Pontiac 3.8

The Pontiac 3.8 was a special SOHC version of the standard 230 cu in (3,768 cc) inline six which shared very little with the Chevrolet: the block was different and used shaft drive outside of the engine for water pump and distributor drive and the famous OHC with a fiberglass reinforced timing belt, first introduced for the 1966 Tempest and used in two versions, one with a single one barrel carburetor and 165 hp, and a second Sprint version with a quadrajet 4 bbl. at 207 hp.[6] An optional W53 version for the Firebird produced 215 hp (160 kW). The Pontiac 3.8 was replaced by a 250 cu in version for 1968-69. The Sprint version of the 250 OHC made 230 HP.

This engine was used on the following vehicles:

  • 1967-69 Pontiac Firebird
  • 1966-1969 Pontiac Tempest

250

The stroked 250 version produced 155 hp (116 kW) for Chevrolet and GMC, with a 37/8 in bore and 317/32 in stroke. Between 1975 and 1984, an integrated cylinder head was produced (intake manifold and cylinder head were a single casting with a bolt on exhaust manifold), with one-barrel intakes for passenger cars, and two-barrel intakes for trucks after 1978.

During the mid-1970s, the Buick 231 and Chevrolet 90-Degree 4.3L V6 engine (essentially a 350 cubic-inch small-block Chevy V-8 with the two rear cylinders removed) were replacing the Chevrolet 250 for use in passenger cars and light duty trucks/vans. Passenger car use of the 250 cu in (4,093 cc) engine was discontinued after the 1979 model year for North America (along with the Chevrolet 292), since the six was restricted to light truck usage (the 4.1 was discontinued after 1984 in North America, where the Vortec 4.3 V6 became the base engine). Brazil held on to the 250 (known as the 4.1 there) until 1998 for passenger cars, when the Chevrolet Omega A was replaced by rebadged Australian Holdens. It was used in Brazil until 2001 in Chevrolet Silverado when the engine line was discontinued. The Brazilian produced sixes gained multipoint fuel injection and redesigned cylinder heads which had smaller intake ports. It would be GM's final inline six until the introduction of the GM Atlas engine in late 2001. It was also used for a number of large sedans by Chevrolet of South Africa.

This engine was used on the following vehicles:

  • 1966–1984 Chevrolet (passenger cars to 1979, trucks/vans to 1984)
  • 1968–1974 Chevrolet 400 Super Sport (Argentina)
  • 1972–1974 Chevrolet 400 Rally Sport (Argentina)
  • 1970–1976 Pontiac Firebird
  • 1970 Pontiac Tempest
  • 1970–1976 Pontiac LeMans
  • 1968–1969 Buick Special
  • 1968–1972 Oldsmobile F-85
  • 1975–1976 Oldsmobile Cutlass
  • 1971–1975 Pontiac Ventura
  • 1968–1971 Buick Skylark
  • 1973–1975 Buick Apollo
  • 1967–1979 Chevrolet Camaro
  • 1969–1979 Checker Marathon
  • 1970–1974 Puma GTB (Brazil)
  • 1971–1992 Chevrolet Opala (Brazil)
  • Chevrolet Constantia (South Africa)
  • 1973-1982 Chevrolet Commodore (South Africa)[5]
  • 1979-1982 Chevrolet Senator (South Africa)[5]
  • 1979–1994 Chevrolet Veraneio (Brazil)
  • 1988–1992 Puma AMV (Brazil)
  • 1995–1998 Chevrolet Omega A (Brazil)
  • 1998–1999 Chevrolet Tahoe (Argentina)
  • 1998–1999 Chevrolet Silverado - (GMT400) (Brazil)
250-S

When the long duration races restarted in Brazil, in 1973, the Opala found a great competitor, the Ford Maverick, which was powered by an engine almost one liter larger in displacement. It took Bob Sharp and Jan Balder, who shared a ride to second place in the "24 Hours of Interlagos" in August of that year in an Opala, to pressure GMB to field a more powerful racing engine.

By coincidence, engine development manager Roberto B. Beccardi was working on this engine hop-up project out of his own initiative, but lacked factory support or approval. This impulse came right from these two pilots.

Thus, in July 1974, GM started to offer the 250-S engine as an option for the Opala 4100. It was slightly different from the version launched two years later: the project engine was similar to the four-cylinder units, did not get a vibration damper, and used the cooling fan from the standard 2500, with four blades instead of six.

The Opala was now much faster than the Maverick GT and Ford did not waste time. It quickly homologated a version with four-barrel carburetor, called "Quadrijet" in Brazil (no relationship to GM's own Rochester Quadrajet), with performance roughly equivalent to the 250.[citation needed]

The 250-S has 171 Horsepower and 229.7 lb.-ft. at 2,400 rpm.

Opala SS Chevrolet Opala SS 250-S in drag race
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  • 1974–1980 Chevrolet Opala SS (Brazil)
  • 1977–1980 Chevrolet Opala Caravan SS (Brazil)
  • 1981–1988 Chevrolet Opala - All Line (Brazil)
  • 1974–1987 Puma GTB (Brazil)
  • 1978–1988 Santa Matilde SM4.1 (Brazil)
L22

The L22 was a 250-cubic-inch (4.1 L) I6 engine produced from 1967 to 1979. The '78 Camaro had 105 horsepower (78 kW) and 190 ft·lbf (260 N·m) of torque with the 250.

LD4

The LD4 was a 250-cubic-inch (4.1 L) I6 engine produced strictly in 1978.

LE3

The LE3 was a 250-cubic-inch (4.1 L) I6 engine produced from 1979 to 1984.

292

The 292 cu in (4.8 L) engine was used in Chevrolet and GMC trucks as well as some full-sized Chevrolet cars beginning in the early 1960s; the block deck is taller, along with a relocated passenger-side engine mount. Flywheel bolt pattern is the same as the six and V8 - with 1/2" bolts for the flywheel if produced after the 1966 model year. Production of the engine was shifted to Mexico in 1980, and later variants of this engine were marketed as the "L25". The 292 retained the separate intake (with a Rochester Monojet carburetor) and exhaust manifolds as used with the short deck motors (194-250). It was GM's last pushrod straight-six engine used from 1977 to 1988 in Chevrolet trucks, including UPS truck chassis. Outputs in 1988 (only): 165 hp at 3,800 rpm and 280 lb. ft. at 1,600 rpm.

Eventually the L25 was replaced by the 4.3 L 90-degree V6.

GMC engines

It has been suggested that this section be split into a new article titled GMC straight-6 engine. (Discuss) (May 2016)

GMC as a marque really only produced a few engine designs, the straight six, a V8, and a V6 which was also available as a V12 for a brief period. GMC used many engines from other GM divisions, as noted below.

228

GMC replaced the Pontiac 223 with their own 228-cubic-inch (3.7 L) 228 in 1939. This OHV (overhead-valve) engine was produced through 1953. This is the smallest low-deck engine, all three of which have 3.8125" stroke and 3.5625" bore, with 7" connecting rods.

236

GMC also developed an OHV/pushrod engine in 1939. The 236-cubic-inch (3.9 L) 236 was produced through 1955. This is a low-deck engine. The bore was 3.625".

248

Those same years (1939–1955), GMC produced a 248-cubic-inch (4.1 L) engine, the 248, which was similar to the 236. This is the largest low-deck engine. The bore was 3.71875".

256

The 256-cubic-inch (4.2 L) 256 was different from the 236 and 248. It was also an OHV/pushrod engine, and was built for just two years, 1940 and 1941. This is the smallest raised-deck engine, all three of which have 4" stroke and 7" connecting rods. The bore was 3.6875".

270

The last GMC-only straight six was the 270-cubic-inch (4.4 L) 270. It was produced from 1941 through 1963, and was an OHV/pushrod engine. This is a raised-deck engine. The bore was 3.78125".

302

The 301.6 (4.9L) GMC inline six was produced from 1952 to 1960, when it was replaced by the V6. It has a 4.00" bore and a 4.00" stroke. This is the largest raised-deck engine. It was originally designed for the GMC military M135 and M211. It was used in military 2.5 ton trucks with the HydraMatic transmission; however, the engine was a sealed engine for snorkel/submersion use, had an electric fuel pump, and other features such as a deep sump oil pan. From 1952 to 1959, GMC manufactured the civilian 302 engine, which was not sealed, had a mechanical fuel pump, and used a "standard" oil pan. This engine was popular with hotrod enthusiasts because it delivered tremendous power for an inline six engine at the time (although now obsolete), is truck built with a heavy cast block, and can take quite a bit of abuse.

426

The 425.6 (7.0L; 4.25"x5.0") GMC inline six appeared in 1940s 4x4 Cab Over Engine (COE) trucks made in Pontiac, MI. It also appeared in large GMC trucks in the 1950s.

503

The 502.7 (8.2L; 4 9/16" x 5 1/8") GMC inline six was more numerous than the 426 inline six, but beginning and ending dates are unknown. The GMC 630 Series of the early 1950s offered the 550.

Atlas

Main article: GM Atlas engine

In 2002, GM announced a family of straight six engines, the Atlas. Branded by GM under the Vortec name, the Vortec 4200 or Atlas LL8 was the last straight six available to the GM family of vehicles.

See also

  • List of GM engines
  • GMC V6 engine
  • GMC V8 engine
  • Chevrolet Straight-4 engine
  • GM Atlas engine

References

  1. ^ a b Leroux, Bruno (2012-11-15). "Le saviez-vous?" [Did you know?]. La Vie de l'Auto (in French). Fontainebleu Cedex, France: Éditions LVA (1533): 8. 
  2. ^ a b c Flory, p.881.
  3. ^ Holden Abroad, Restored Cars #220, Sep-Oct 2013, page 45
  4. ^ a b 1970 Holden HT Brougham, Restored Cars #174, Jan-Feb 2006, pages 27 to 28
  5. ^ a b c Mastrostefano, Raffaele, ed. (1985). Quattroruote: Tutte le Auto del Mondo 1985 (in Italian). Milano: Editoriale Domus S.p.A. pp. 186–187. ISBN 88-7212-012-8. 
  6. ^ Gunnell, John; Kowalke, Ron (1995). Standard Catalog of Pontiac, 1926-1995. Iola, WI: Krause Publications, Inc. pp. 92–93. ISBN 0-87341-369-5. 
  • FAQ Stovebolt.com — What is a Stovebolt?
  • Chevrolet "Stovebolt" Six by Jack Nerad — The story of the Chevrolet "Stovebolt" Six.
  • Classic definition of a Stovebolt — by the Mid State Antique Stock Car Club

External links

  • Sheridan's 1946 Chevy Truck — 1941–46 Chevrolet truck photos; lots of information.
  • Stovebolt.com — Online information resource and discussion forums for pre-'73 Chevrolet & GMC trucks.
  • 67–72chevytrucks.com — Founded for the 67-72 trucks, it is now an online forum community devoted to all years & models full size Chevy/GMC Trucks. From stock originals, to mud trucks, to show stoppers… our members have them all.
  • chevytrucks.org — Specializing in information on 1941–59 Chevrolet trucks; how-to articles, pictures, history, etc.
  • "The Art Deco Series" — This site is dedicated to the history and preservation of the Chevrolet & GMC commercial haulers that were produced just before, during, and just after World War II, 1941–46.
  • OldTruckNetwork.com — The No. ? online information resource for old trucks and politics.

en.wikipedia.org

Chevrolet small-block engine

The Chevrolet small-block engine is a series of automobile V8 engines built by the Chevrolet Division of General Motors using the same basic small (for a US V8 of the time) engine block. Even though the first big-block engines were smaller in displacement than the largest small block engine, the small blocks were almost all under 400 cu in (6.6 L) with most of the big block engines being above that. The small blocks' small physical size also set them apart from their massive physical size cousins, the big blocks. Retroactively referred to as the "Generation I" small-block, it is distinct from subsequent "Generation II" LT and "Generation III/IV" LS, and "Generation V" (LT/EcoTec3) engines. Engineer Ed Cole, who would later become GM President, is credited with leading the design for this engine.

Production of the original small-block began in the fall of 1954 for the 1955 model year with a displacement of 265 cu in (4.3 L), growing incrementally over time to 400 cu in by 1970. Several intermediate displacements appeared over the years, such as the 283 cu in (4.6 L) that was available with mechanical fuel injection, the 327 cu in (5.4 L), as well as the numerous 350 cu in (5.7 L) versions. Introduced as a performance engine in 1967, the 350 went on to be employed in both high- and low-output variants across the entire Chevrolet product line.

Although all of Chevrolet's siblings of the period (Buick, Cadillac, Oldsmobile, Pontiac and Holden) designed their own V8s, it was the Chevrolet 350 cu in small-block that became the GM corporate standard. Over the years, every American General Motors division except Saturn used it and its descendants in their vehicles.[1]

Finally superseded by GM's Generation II "LT" and Generation III "LS" V8s in the 1990s and discontinued in 2003, the engine is still made by a GM subsidiary in Mexico as a crate engine for replacement and hot rodding purposes. In all, over 100,000,000 small-blocks (as of November 29, 2011) have been built in carbureted and fuel injected forms since 1955. In many respects, the later Generation II and Generation III engines still in production today for various vehicles still trace some of their design lineage to the "small-block" design concept first laid down by Ed Cole and his team.

The small-block family line was honored as one of the 10 Best Engines of the 20th Century by automotive magazine Ward's AutoWorld.[1]

In February 2008 a Wisconsin businessman reported that his 1991 Chevrolet C1500 pickup had logged over 1 million miles without any major repairs to its small block V8 engine. (Source: The Flint Journal, February 17,2008).

Overview

The first generation of Chevrolet small-blocks began with the 1955 Chevrolet 265 cu in V8 offered in the Corvette and Bel Air. Soon after being introduced, it quickly gained popularity among stock car racers, becoming known as the "Mighty Mouse" motor, after the popular cartoon character of the time, with the simpler "Mouse" becoming much more common as time went on.[2]

By 1957 it had grown to 283 cu in. Fitted with the optional Rochester mechanical fuel injection (FI), it was one of the first production engines to make 1 hp (0.75 kW) per 1 cu in (0.016 L). The 283 would later be extended to other Chevrolet models, replacing the old style 265 V8s.

A high-performance 327 cu in variant followed, turning out as much as 375 hp (280 kW) and increasing horsepower per cubic inch to 1.15 hp (0.86 kW).

It was, however, the 350 cu in series that came to be the best known Chevrolet small-block. Installed in everything from station wagons to sports cars, in commercial vehicles, and even in boats and (in highly modified form) airplanes, it is by far the most widely used small-block of all-time.

Though not offered in GM vehicles since 2003, the 350 cu in series is still in production today at General Motors' Toluca, Mexico plant under the company's "Mr. Goodwrench" brand, and is also manufactured as an industrial and marine engine by GM Powertrain under the Vortec name.

From 1955 to 1974, the small-block engine was known as the "Turbo-Fire" V8.

3.875 in. bore family (1955–1973)

All Chevrolet V8s, from the big-blocks to today's LS7 and LS9, evolved from the 265/283 cu in small-block family. Of the three engines in this family, two of them, the 265 and the 283, have gone down in automotive history. The first of this family was the 265, introduced in 1955. The 265 had a 3.75 in (95.25 mm) bore. The stroke of the 265 was 3.00 in (76.20 mm), like the 283. The 283, famous for being one of the first engines to make one hp per cubic inch, is also famous for being the evolutionary stepping stone that would later give rise to small blocks and to the "W" blocks, ultimately culminating in the Chevrolet big-blocks. The last of this family was the 307 cu in (5.0 L), which was a stroked 283 with a medium journal.

265

The 265 cu in "Turbo-Fire" V8 was the first Chevrolet small-block, although the first Chevrolet V8 was produced from 1917 to 1918. Designed by Ed Cole's group at Chevrolet to provide a more powerful engine for the 1955 Corvette than the model's original "stovebolt" in-line six, the 162 hp (121 kW) 2-barrel debut version went from drawings to production in just 15 weeks.[3]

Cole's design borrowed the valve train design scheduled to be used at the time in the Pontiac V8. Internal GM rules at that time were that once an automotive division had introduced a technological innovation no other GM division could use it for a period of two years. The stud mounted independent ball rocker arm design patented by Pontiac engineer Clayton Leach was scheduled for introduction in the Pontiac 1955 V8. GM forced the Pontiac division to share its valve train design in Chevrolet's new 265 V8 in 1955, so that in the end both engines were introduced the same year with the same valve train design.[3]

A pushrod engine with hydraulic lifters, the small-block was available with an optional four-barrel Rochester carburetor, increasing engine output to 180 hp (130 kW), or 195 hp (145 kW) in the Corvette. The short-stroke (3.75 in bore, 3 in stroke) engine's 4.4 in (111.8 mm) bore spacing would continue in use for decades.[4]

Also available in the Bel Air sedan, the basic passenger car version produced 162 hp with a two-barrel carburetor. Upgraded to a four-barrel Rochester, dual exhaust "Power Pack" version, the engine was conservatively rated at 180 hp, and with the "Super Power Pack" it was boosted up to the power level of the Corvette.[4]

A shortcoming of the 1955 265 was its lack of any provision for oil filtration built into the block, instead relying on an add-on filter mounted on the thermostat housing, and that was an "option only". In spite of its novel green sand foundry construction, the '55 block's lack of adequate oil filtration leaves it typically only desirable to period collectors.[citation needed]

The 1956 Corvette introduced three versions of this engine – 210 hp (160 kW) with a single 4-barrel carburetor, 225 hp (168 kW) with twin 4-barrels, and 240 hp (180 kW) with two four-barrel carburetors and a high-lift camshaft.[4]

283

The 265 cu in V8 was bored out to 3.875 in (98.4 mm) in 1957, giving it a 283 cu in displacement. The first 283 motors used the stock 265 blocks. However, the overbore to these blocks resulted in thin cylinder walls. Future 283 blocks were recast to accept the 3.875 bore. Five different versions between 185 hp (138 kW) and 283hp were available, depending on whether a single carb, twin carbs, or fuel injection was used. Fuel injection yielded the most power topping out at 315 hp (235 kW) in 1961. Horse power was up a bit each year for 1958, 1959, and 1960. The 1957 Ramjet mechanical fuel injection version produced an even one hp per one cu in (61 hp (45 kW)/1 L (61 cu in)), an impressive feat at the time. This was the third U.S.-built production V8 to produce one horsepower per cubic inch.

Besides being available in the Chevrolet line, it was optional in Checker Taxis beginning in 1965.[5] A version of it that was built by GM Canada was also available in Studebakers produced in Canada for 1965 & 1966.

307

A 307 cu in version was produced from 1968 through 1973. Engine bore was 3.875 inches with a 3.25-inch (82.6 mm) stroke. All 307s had large 2.45 in (62.23 mm) journals - the crankshaft is sourced from the 327. Pistons used with the 307 share the same pin height as the 327 but retaining the 283s bore size (prior to 1968 it was possible to stroke a 283 into a 307 where aftermarket pistons had to be used). This engine was also used by Holden in Australia and by General Motors' South African arm.[6]

4.00 in bore family (1962–1998)

Originally intended as the performance block, this engine family through the 350 cu in became an all purpose engine that saw use in many applications from Corvettes to vans. All engines in this family share the same block dimensions and sometimes even the same casting number; the latter meaning engines were of the same block, but with different strokes (e.g. the casting number 3970010 was used by all three engines: 302, 327, and 350). This engine family was updated in 1968 for the use of 2.45 in medium-sized journals. The first engine in this family was the small journal 327 in 1962 and the last being 2000s medium journal 350 in pickup trucks and commercial vehicles. The medium journal 350 was further developed into the "Generation II" LT1/4 350 in the early 1990s.

302

In 1966, General Motors designed a special 302 cu in (4.9 L) engine for the production Z/28 Camaro in order for it to meet the Sports Car Club of America (SCCA) Trans-Am Series road racing rules limiting engine displacement to 305.1 cu in (5.0 L) from 1967 to 1969. It was the product of placing the 283 cu in 3.00 in stroke crankshaft into a 4.00 in (101.60 mm) bore 327 cu in cylinder-block. The 1967 302 used the same nodular cast-iron crankshaft as the 283, with a forged-steel crank that was also produced. This block is one of three displacements, 302/327/350, that underwent a crankshaft bearing diameter transformation for 1968 when the rod-journal size was increased from the 2.00 in (50.80 mm) diameter small-journal to a 2.10 in (53.34 mm) large-journal and a main-journal size that was increased from 2.30 in (58.42 mm) to 2.45 in (62.23 mm). The large-journal connecting rods were thicker (heavier) and used 3/8 in diameter cap-bolts to replace the small-journal's 11/32. 1968 blocks were made in 2-bolt and 4-bolt versions with the 4-bolt center-three main caps each fastened by two additional bolts which were supported by the addition of heavier crankcase main-web bulkheads. When the journal size increased to the standard large-journal size, the crankshaft for the 302 was specially built of tufftride-hardened forged 1053-steel and fitted with a high-rpm 8.00 in (203.20 mm) diameter harmonic balancer. It had a 3/4-length semi-circular windage tray, heat-treated, magnafluxed, shot-peened forged 1038-steel 'pink' connecting rods, floating-pin in `69, forged-aluminum pistons with higher scuff-resistance and better sealing single-moly rings. Its solid-lifter cam, known as the "30-30 Duntov" cam named after its 0.030 in (0.76 mm)/0.030 in hot intake/exhaust valve-lash and Zora Arkus-Duntov (the first Duntov cam was the 0.012 in (0.30 mm)/0.018 in (0.46 mm) 1957 grind known as the '097, which referred to the last three digits of the casting number) the "Father of the Corvette", was also used in the 1964-1965 carbureted 327/365 and fuel injected 327/375 engines. It used the '202' 2.02 in (51.31 mm)/1.60 in (40.64 mm) valve diameter high-performance 327 double-hump `461 heads, pushrod guide plates, hardened 'blue-stripe' pushrods, edge-orifice lifters to keep more valvetrain oil in the crankcase for high-rpm lubrication, and stiffer valvesprings. In 1967, a new design high-rise cast-aluminum dual-plane intake manifold with larger smoother turn runners was introduced for the Z/28 that the LT-1 350 cu in 1969 Corvette and 1970 Z/28 engines were equipped with until the Q-jet carburetor returned in 1973. Unlike the Corvette, the exhaust manifolds were the more restrictive rear outlet 'log' design to clear the Camaro chassis's front cross-member. It had a chrome oil filler tube in the front of the intake manifold next to the thermostat housing from 1967 to 1968. The first year had unique chrome valve covers with Chevrolet stamped into them without an engine displacement decal pad. In 1968, the engine had the chrome covers, but without the Chevrolet name, connected to a PCV valve and a chrome 14.00 in × 3.00 in (355.60 mm × 76.20 mm) drop-base open-element air cleaner assembly fitted with a crankcase breather on a 780 cu ft/min (22 m3/min) vacuum secondary Holley 4-Bbl carburetor. A 'divorced' exhaust crossover port heated well-choke thermostat coil was used to provide cleaner and faster engine warm-up. Its single-point distributor had an ignition point cam designed to reduce point bounce at high rpm along with a vacuum diaphragm to advance ignition timing at idle and part-throttle for economy and emissions. Pulleys for the balancer, alternator, water-pump, as well as optional power-steering, were deep-groove to retain the drive belt(s) at high rpm. In 1969, the 302 shared the finned cast-aluminum valve covers with the LT-1 350 Corvette engine. Conservatively rated at 290 hp (220 kW) (SAE gross) at 5800 rpm and 290 lb·ft (393 N·m) at 4800, actual output with its production 11:1 compression ratio was around 376 hp (280 kW) with 1.625 in (41.28 mm) primary x 3.00 in secondary Sanderson tubular headers that came in the trunk when ordered with a 1967 Z/28, and associated carburetor main jet and ignition timing tuning[citation needed]. In 1968, the last year for factory headers, they had 1.750 in (44.45 mm) primaries x 3.00 in secondaries. A stock 1968 Z/28 with the close-ratio transmission, optional transistorized-ignition and 4.88 gear, fitted with little more than the factory cowl plenum cold-air hood induction and headers, was capable of running 12.9 second/108 mph (174 km/h) 1/4-mile times on street tires.

After the 1967 Trans-Am campaign with the 4-Bbl induction system producing more horsepower than the competing auto makers' 8-Bbl systems, for 1968 Chevrolet developed a factory 'cross-ram' aluminum intake-manifold package using two Holley 600 cu ft/min (17 m3/min) mechanical secondary carburetors for Trans-Am racing. It was available only as off-road service parts purchased over the Chevrolet dealership parts counter. With the Chevrolet '140 1st-design off-road cam, the package increased a stock 302's horsepower from 360 hp (270 kW) to approximately 400 hp (300 kW). Chevrolet went so far as to carry the positive crankcase ventilation (PCV) system over to the cross-ram induction system to retain emissions compliance mandated for US-produced cars beginning in 1967, that also provided full-throttle crankcase pressure venting to the intake air to burn its vapors. Engines prepared for competition use were capable of producing 465 hp (347 kW) with little more than the 8-Bbl induction, ported heads with higher pressure valvesprings, roller rocker arms, and the '754 2nd-design road-race cam. 1967/1968 models' cowl-induction system had an enclosed air-cleaner assembly ducted from its passenger side into the firewall cowl above the heater core. In 1969, factory Z/28's could be ordered with the ZL-1 aluminum-block 427 adaption of the 1967 L-88 427 Corvette cowl-induction 'ZL-2' hood available for both single and dual four-barrel induction systems that were sealed to the air cleaner base ensuring dense cooler, high-pressure, oxygen-laiden air from the center of the base of the windshield was supplied to the engine for combustion smoothness and maximum power production. Another popular service-parts-only component used on the 302 was the magnetic-pulse Delco transistor-ignition ball-bearing distributor. Introduced in 1963 on Pontiac's 389 and 421 drag racing engines, General Motors fitted it to the 1966? Z/28 before they used it on the L88 427 cu in (7.0 L) Corvette. It eliminated the production breaker-point ignition allowing greater spark energy and more stable ignition timing at all engine speeds including idle. This was one of the least talked about yet most transformative and comprehensive performance and durability upgrades of its time. Many of the 302s off-road service parts were the development work of racers like Roger Penske. Every part in a SCCA Trans-Am engine had to be available through local Chevrolet parts departments to encourage their use by anyone who wanted them.

While the 302 became a strong Limited Sportsman oval track racing engine in the hands of racers like Bud Lunsford in his 1966 Chevy II, its bore/stroke and rod/stroke geometries made it a natural high-rpm road-racing engine and were responsible for its being among the more reliable production street engines homologated for full competition across all the American makes, winning back-to-back Trans-Am Championships at the hands of Mark Donohue in 1968 and 1969. However, with engines built by Al Bartz, Falconer & Dunn and Traco Engineering, the pinnacle of the 302's use in professional racing was its being the primary engine that powered the outstanding but overshadowed 1968-1976 Formula 5000 Championship Series, a SCCA Formula A open-wheel class designed for lower cost. The engine was also popular in Formula 5000 racing around the world, especially in Australia and New Zealand where it proved more powerful than the Repco-Holden V8. Weighing 1,350 lb (610 kg), with a 525–550 hp (391–410 kW) iron block and head engine positioned near the car's polar moment of inertia for responsive turn pivoting, a Hewland 5-spd. magnesium transaxle, and 10 in wide 13 in front/20 in wide 15 in rear magnesium wheels, it produced incredibly exciting racing. They ran 0–60 mph (0–97 km/h) in 2.8 seconds and over 180 mph (290 km/h). Reminiscing about the series, mid-70s Australian F5000 driver Bruce Allison said, “We never used first gear at the start. We started in second, and even then there was so much torque, you’d get wheelspin through third and fourth gears.” Prepared with a Lucas-McKay mechanically timed individual-stack magnesium fuel-injection induction system that was paired with ported production car double-hump iron heads, a rev-kit fitted roller lifter camshaft, roller bearing rocker arms, and a virtually stock production crankshaft, it had a lasting impact on the series' ability to conduct high car-count finishes and close competition events by the degree of mechanical success it provided to a series filled with star international Grand Prix drivers like David Hobbs, Brian Redman, Jody Scheckter and Mario Andretti.

327

The 327 cu in V8, introduced in 1962, had a bore of 4 in and a stroke of 3.25 in (82.55 mm). Power ranged from 210 hp to 375 hp depending on the choice of carburetor or fuel injection, camshaft, cylinder heads, pistons and intake manifold. In 1962, the Duntov solid lifter cam versions produced 340 hp (250 kW), 344 lb·ft (466 N·m) with single Carter 4-barrel, and 360 hp, 352 lb·ft (477 N·m) with Rochester FI. In 1964, horsepower increased to 365 hp (272 kW) for the now dubbed L-76 version, and 375 hp for the fuel injected L-84 respectively, making the L-84 the most powerful naturally aspirated, single-cam, production small block V8 until the appearance of the 385 hp (287 kW), 385 lb·ft (522 N·m) Generation III LS6 in 2001. This block is one of three displacements that underwent a major change in 1968/1969 when the main journal size was increased from 2.30  to 2.45 in. It's also interesting to note that in 1965 Chevrolet released the now legendary L-79, which was nothing more than an L-76 (11.0:1 forged pop-up pistons, forged steel rods and crank, 2.02 Corvette heads), but with the 30-30 Duntov cam replaced by the #151 hydraulic cam.

In 1966, Checker began offering the 327 as an option.[7] The Avanti II and its successors were powered by the 327 and later versions of the small-block V8.

In 1968, the 327 was exported to Australia for use in the Holden HK Monaro GTS327. The engine was used in the Monaro after development of the locally made Holden V8 engine fell behind schedule. The 327 was replaced in the 1969 Monaro by the 350.

350

The 350 cu in, with a 3.48-inch (88.39 mm) stroke, first appeared as a high-performance L-48 option for the 1967 Chevrolet Camaro. One year later it was made available in the Chevrolet Nova, and finally in 1969 the rest of the Chevrolet line could be ordered with a 350. As had been the case with earlier versions of the small-block, the 350 was available in many different Canadian Pontiac vehicles, which unlike their US counterparts, used Chevrolet chassis and drivelines.

Many variants followed:

L46

Years: 1969-1970

The L46 became an optional engine for the 1969 Chevrolet Corvette. It was a higher performance version of the base 350 cu in V8 with casting number 186 2.02 in/1.60 in valve heads and had an 11:1 compression ratio (high octane gas must be used) and produced 350 hp (260 kW).[8] It was also available in 1970. 4bbl Quadrajet carburetor and L46 hydraulic cam, dome piston (+0.16 cu in (2.6 cc)), 186 heads, and a four-bolt block.

L48

Years: 1967–1980

The L48 is the original 350 cu in, solely available for 1967 in the Super Sport (SS) version of Camaro (1967-up) or Chevy II/Nova in 1968-1979. In 1969 it was used in almost all car lines; Camaros, Caprices, Impalas, El Caminos, Chevelles & Novas. The 1969 L48s use a hydraulic cam, 4bbl Quadrajet carburetor, cast pistons, 4-bolt main casting number 010 Blocks & casting number 041 or 186 heads. Power output was 300 hp (220 kW) SAE and 380 lb·ft (515 N·m) torque. Compression ratio was 10.25:1. The compression ratio of the L48 was lowered to 8.5:1 in 1971.

In 1972 the only way to get a L48 (4bbl V8) in a Chevrolet Nova was to get the SS Package. This is indicated by the fifth digit in the VIN being a "K". 1972 was the only year you could verify the SS package by the VIN.

The L48 engine was also exported to Australia, where it appeared in the Holden Monaro from 1969 through 1974, and in the Statesman (automobile) from 1971 through 1974. Towards the end of the HQ series in 1973-74, due to US emissions regulations, the performance of these imported engines had dropped to a level similar to or perhaps lower than Holden's own locally manufactured 308 cu in (5,050 cc) V8, which was not yet subject to similar regulations, leading to Holden's discontinuation of the motor.

The L48 V8 was the standard engine in the 1975–1980 Chevrolet Corvette. The L48 V8 Corvette engine produced 165 hp (123 kW) in 1975. Power increased to 180 hp in 1976 and stayed the same in 1977. The 1978 saw 175 hp (130 kW) for California or high altitude areas and 185 hp for everywhere else. Power increased to 195 hp in 1979 and decreased to 190 hp (140 kW) in 1980.[8]

L65

The 2bbl carburetor 145 hp (108 kW) version of the LM1 350. Produced until the 1976 model year.

LM1

The LM1 is the base 350 cu in with a 4-barrel carburetor (usually with a Rochester Quadrajet) 155–175 hp (116–130 kW) engine in passenger cars to 1979 as a retail option (its final use with a retail passenger car was the 1981 Camaro Z28) and police package 9C1 A/G (Malibu to 1981) and B-bodies (Caprice, Impala) until 1988 retail market GM rear wheel drive/V8s sold to the general public had a maximum 5.0 liters displacement with the exception of its musclecar survivors e.g. Corvette and F-bodies (Camaro IROC Z or Trans Am). Throughout its lifespan, it received either a points, electronic, and/or computer-controlled spark system, to conventional and feedback carburetors. The LM1 was superseded by the L05 powerplant after 1988.

ZQ3

Years: 1969-1974

The ZQ3 was the standard engine in the 1969–1974 Chevrolet Corvette. It was a 300 hp version of the 350 cu in small-block, with 10.25:1 compression and hydraulic lifters. It used a Rochester "4MV" Quadra-Jet 4-barrel carburetor.[9]

Note: Post-1971 blocks supposedly had a lower nickel content but thicker cylinder deck, and post 1974 heads of the small block Chevrolet used less iron, and were lighter weight, crack-prone, and less powerful because of the lower compression ratios used.[citation needed]

In 1971, power decreased to 270 hp (200 kW) (gross) and 300 lb·ft (407 N·m) (gross) of torque with 8.5:1 compression. 1972 saw 200 hp (150 kW) (net) and 270 lb·ft (366 N·m) (net) of torque. In 1973 power decreased to 190 hp, but increased slightly in 1974 to 195 hp.[8]

LT-1
For the Generation II V8 used from 1991-1997, see LT1 For the new Generation V V8, see LS-based GM LT1. LT-1 from a 1970 Chevrolet Camaro Z28

Years: 1970–1972

The LT-1 was the ultimate 350 cu in V8, becoming available in 1970. It used solid lifters, 11:1 compression, the '178' high-performance camshaft, and a 780 CFM Holley four-barrel carburetor on a special aluminum intake, with rams' horn exhaust manifolds in the Corvette, Delco transistor ignition and a low-restriction exhaust factory rated at 370 hp (280 kW) in the Corvette, and 360 hp at 6000 rpm and 380 lb-ft at 4000 in the Camaro Z28[10] (the NHRA rated it at 425 hp (317 kW) for classification purposes). Redline was 6500 rpm but power fell off significantly past 6200 rpm. The LT-1 was available in the Corvette, and Camaro Z28. Power was down in 1971 to dual-rated 330 hp (250 kW) (gross)/255 hp (net) and 360 lb·ft (488 N·m) of torque with 9:1 compression, and again in 1972 (the last year of the LT-1, now rated using net only, rather than gross, measurement) to 255 hp and 280 lb·ft (380 N·m).

L82

Years: 1973–1980

The 1973–1974 L82 was a "performance" version of the 350 that still used the casting number 624 76cc chamber "2.02" heads but with a Rochester Quadra-jet 4bbl carburetor and dual-plane aluminum intake manifold, the earlier L46 350 hp 350 hydraulic-lifter cam, and 9:1 compression forged-aluminum pistons producing 250 bhp (`71 was the first year for SAE net hp rating, as installed in the vehicle with accessories and mufflers) and 285 lb-ft of torque. Its cast-aluminum LT-1 valvecovers were painted crinkle-black contrasting with the aluminum manifold and distributor housing. It was down to 205 bhp and 255 lb-ft of torque for 1975. It produced 210 bhp in the Corvette for 1976-1977. The 1978 L82 recovered somewhat, producing 220 bhp and 260 lb-ft in the Corvette and in 1979 it produced 225 bhp in the Corvette. In 1980, its final year, it produced a peak of 230 bhp.[8] This engine was also available on the Chevrolet Camaro.

L81

Years: 1981

The L81 was the only 5.7 L (350 cu in) Corvette engine for 1981. It produced 190 bhp and 280 lb-ft of torque from 8.2:1 compression, exactly the same as the 1980 L48, but added hotter cam and computer control spark advance, replacing the vacuum advance.[9] The L81 was unique in that it was the only Corvette engine that employed a "smart carburetor." The Rochester Quadrajet from 1980 was modified to allow electronic mixture control, and an ECM (Engine Control Module), supplied with data from an exhaust oxygen sensor, modified the fuel/air mixture being fed to the engine.

LS9

Years: 1970-1986

The LS9 was GM's 350 cubic inch truck engine used in C/K/G 10/20 models under 8500 lb GVWR (gross vehicle weight rating). The LS9 used a Rochester 4 bbl carburetor, and its power ratings for 1984 were 165 HP at 3800 rpm, and 275 Lb-ft torque at 1600 rpm. A version using a closed-loop carburetor was used with the California emissions package in its final years. The LS9 and LT9 engines were replaced for 1987 by the L05 TBI (throttle body injection) engines. Most of the small block engines in this timeframe were built at either the Flint Engine plant in south Flint, MI or at St. Catherines, Ontario, CA. The Flint plant was producing about 5200 engines per day in the mid 80's, and had a slower, separate line for the TPI engines used in the Camaro and Corvette. (Source: 1984 Chevrolet Truck Data Book.)

LT-9

Years: 1981-1986[11]

The LT-9 served as GM's truck-based Heavy Emissions[12] variant of the 5.7 L (350 cu in) supplied in K20/K30 pickups, G model passenger and cargo vans (built in Lordstown, OH and later in Flint, MI) and with the P30 chassis used for motorhomes and stepvans.

The LT-9's listed specifications are 160 bhp @ 3800 rpm and 250 lb-ft of torque @ 2800 rpm with 8.3:1 compression.[13] LT-9's were carbureted with Rochester Quadrajets from factory and are generally 4-bolt mains. The LT-9 is often known by VIN code as the "M-code 350."[12] The LT9 was used in models with GVWRs (gross vehicle weight ratings) over 8500 lbs.

L83

Years: 1982, 1984

The 1982 L83 was again the only Corvette engine producing 200 bhp and 285 lb-ft of torque from 9:1 compression. This was again the only engine on the new 1984 'Vette, at 205 bhp and 290 lb-ft of torque. The L83 added Cross-Fire fuel injection (twin throttle-body fuel injection). Since GM did not assign a 1983 model year to production Corvettes, there was also no L83 for 1983.[8]

L98
For the new Generation IV V8, see GM L98.

Years: 1985–1992

The new 1985 L98 350 added tuned-port fuel injection "TPI", which was standard on all 1985–1991 Corvettes. It was rated at 230 bhp for 1985–1986, 240 bhp for 1987-1989 (245 bhp with 3.08:1 rear axle ratio (1988-1989 only)), and 245 bhp in 1990-1991 (250 bhp with 3.08:1 rear axle). Aluminum cylinder heads (Corvette only) were released part way through the 1986 model run, modified for 1987 with D-ports, and continued through the end of L98 Corvette production in 1991 (still used on ZZx 350 crate engines until 2015 when the ZZ6 received the Fast Burn heads).[9] The L98 V8 was optional on Jan. '87–'92 Chevrolet Camaro & Pontiac Firebird models (rated at 225 hp (168 kW)-245 hp (183 kW) and 330 lb·ft (447 N·m)-345 lb·ft (468 N·m)) 1987 versions had 10 hp (7 kW) and 15 lb·ft (20 N·m) more and a change to hydraulic roller camshaft. Compression was up again in 1990 to 9.5:1 Camaro/Firebird and 10:1 Corvettes, but rated output stayed the same.

L05

The L05 was introduced in 1987 for use in Chevrolet/GMC trucks in the GMT400 (introduced in April 1987 as 1988 models) and the R/V series trucks such as the K5 Blazer, Suburban, and rounded-era pickups formerly classed as the C/K until 1991 which includes chassis cabs and 4-door crew cabs. The L05 was also used in the G van models and the P30 Step vans. Additionally, the L05 was used in 9C1-optioned Caprices, and in the following vehicles:

  • 1992/1993 Buick Roadmaster sedan and station wagon
  • 1990–1992 Cadillac Brougham (optional engine)
  • 1993 Cadillac Fleetwood
  • 1989-1993 Chevrolet Caprice 9C1 police package (roller cam); 1A2-optioned special service station wagon
  • 1992/1993 Chevrolet Caprice Wagon (optional engine)
  • 1993 Chevrolet Caprice LTZ
  • 1992 Oldsmobile Custom Cruiser Wagon (optional engine)
  • 1995-1996 AM General Hummer h2

L05s were used primarily with casting number 14102193 (64cc combustion chambers) cylinder heads with swirled intake ports - the intake ports were designed for fuel economy (the design was also shared with the 103 heads used on the 4.3L with TBI). The swirl ports (known to GM as a vortex chamber) along with the irregular shape of the combustion chambers limit the airflow and horsepower output where they did not provide a fast burn, later phased in with the 1996+ Vortec heads. A majority of the L05s used with the truck/vans had conventional flat tappet camshafts while the Caprice 9C1 (1989–93) had a roller cam. L05 usage was replaced by the LT1 after 1993 in GM B-Bodies until production ceased in 1996.

A single belt (serpentine belt) accessory drive was introduced on the L05, the 5.0L L03 and the 4.3L V6 LB4 engines used in the 1988 GMT400 models but not on the older R/V models (R/V models received the serpentine belt drive in 1989 when the front grille was facelifted in appearance to the GMT400 lineup).

In February 2008 a Wisconsin businessman reported that his 1991 Chevrolet C1500 pickup had logged over 1 million miles without any major repairs to its L05 engine. (Source: The Flint Journal, February 17,2008) The article also mentioned that the Flint Engine plant that built the engine, had produced 45 million engines in its 45 year history, before closing in 1999.

In mid-1996 the L05 was equipped with heads used in the 1996 G30.

L31

The Vortec 5700 L31 (Vin code 8th digit "R") is a V8 truck engine. Displacement is 5.7 L. It is the last production Generation I small-block from Chevrolet. The cylinder heads feature combustion chambers and intake ports very similar to those of the LT1 V8, but without the reverse-flow cooling. As such, the L31 head is compatible with all older small-blocks, and is a very popular upgrade. It offers the performance of more expensive heads, at a much lower cost. It does, however, require a specific intake manifold (A 5.7L, 350 CI L31, Vortec engine has eight bolts attaching the intake manifold or four per head, as opposed to the traditional six bolts per head twelve in total found on older Chevrolet small blocks). The L31 was replaced by the 5.3 L 5300 LM7. The 2002 model year was the final year for the L31 5.7 L small block V8 whose origins date back to 1955. The Vortec 5700 produces 255 hp (190 kW) to 350 hp (261 kW) at 4600 rpm and 330 lb·ft (447 N·m) to 350 lb·ft (475 N·m) of torque at 2800 rpm. It is currently being produced as a crate engine for marine applications and automotive hobbyists as the 'RamJet 350' with minor modifications. Known as the GEN 1+, this was the final incarnation of the 1955-vintage small block, ending production in 2005 with the last vehicle being a Kodiak/Topkick HD truck. Volvo Penta and Mercury Marine still produces the L31. The "MARINE" intake is a potential upgrade for L31 trucks despite its cast iron construction. Using this "MARINE" intake will allow the use of common types of Bosch-style injectors with various flow rates while still maintaining emission compliance.

L31 applications:

  • 1996–2002 Chevrolet Express/GMC Savana full-size vans
  • 1996–1999 Chevrolet/GMC C/K full-size trucks
  • 1996–1999 Chevrolet Suburban/GMC Suburban full-size long-wheelbase SUVs
  • 1996–2000 Chevrolet Tahoe/GMC Yukon (and 2000 Tahoe Limited and 2000 Tahoe Z71 models) full-size short-wheelbase SUVs
  • 1999–2000 Cadillac Escalade

TBI L31 applications

  • 1996 G-Series vans over 8,500 lb (3,856 kg) GVW w/ 4L80E transmission

Special applications

  • Oscar Mayer Wienermobile
  • Isuzu Box Trucks

4.125 in bore family (1970–1980)

400

A Small Block 400ci V8 in a 1975 Avanti II

The 400.9 cu in (6,570 cc) is the only engine in this family and was introduced in 1970 and produced for 10 years. It has a 4.125-inch (104.8 mm) bore and a 3.75-inch (95.3 mm) stroke. The 400 differed from other small blocks in that the cylinders were siamesed and therefore required 'steam' holes in the block, head gaskets, and heads to help alleviate 'hot-spots' in the cooling system at the point above the siamesed cylinders. Overheating and damage are likely if head gaskets or heads without 'steam' holes are used on a 400 block. The 400 is the only engine that uses a 2.65" main bearing journal and a 2.10" rod bearing journal. The connecting rod was also 400 specific being 5.565" as opposed to the 5.7" rod used in all other small block Chevrolet engines. The 400 was made in 4-bolt main journal from 1970 to 1972 and in 2-bolt main journal from 1973 to 1980. The 400 can have either 2 or 3 freeze-plugs per side though all 400 blocks have the provisions for a 3rd freeze-plug on each side. The 400 was rated at 245–265 horsepower (gross[150–180 HP net]) through its life. The 400 saw extensive use in full-size Chevrolet and GMC trucks; K5 Blazer/Jimmy, 1/2-ton, 3/4-ton, 1-ton, and even larger 'medium duty' trucks had an option to be equipped with a 400. The engine was available in midsize A-Body and full-size B-Body passenger cars until the end of the 1976 model year. Early models produced 265 horsepower with a two-barrel carburetor. All 400s came with a two-barrel carburetor with a four-barrel carburetor option becoming available in 1974.

The 400 was never intended as a high-performance engine and never saw large factory horsepower numbers; however, it did develop a reputation for creating a tremendous amount of torque (up to 400 ft-lbs(g) in 1970) and has since become popular for many types of racing, both on and off road. It was also used for the limited production Avanti for a few years in the 1970s.

3.671 in bore family (1975–1976)

262

The 1975–1976 262 was a 262.3 cu in (4,299 cc) 90° pushrod V8 with an iron block and heads. Bore and stroke were 3.67 in (93 mm) by 3.10 in (78.7 mm). Power output for 1975 was 110 hp (82 kW) and 133 lb·ft (180 N·m) at 3600 rpm. The 262 was replaced by the 305 for the 1977 model year.

This was Chevrolet's second 4.3 L-displacement powerplant; four other Chevrolet engines displaced 4.3 L: the Vortec 4300 (a V6 based on the Chevrolet 350, with two cylinders removed), the original 265 V8 in 1955, a bored version of the stovebolt-era 235 inline six displacing 261 cubic inches, and a derivative of the GenerationII LT engines known as the L99 (using the 305's 3.736-inch bore, 5.94-inch connecting rods, and a 3-inch crankshaft stroke).

This engine was used in the following cars:

  • 1975–1976 Chevrolet Monza
  • 1975 Chevrolet Nova
  • Early 1977 Pontiac Ventura

3.736 in bore family (1976–1998)

305

Designed and built during the era of the gas embargo, CAFE mandates, and tighter emissions, this engine family was designed to become Chevrolet's cost-effective, all-purpose "economy V8" engine line. These were intended to fill the gap where the venerable 283 ('57-'67), & 307 ('68-'73) had been. Bore and stroke were 3.736 in (94.9 mm) by 3.48 in (88.4 mm) (305.2 cu in (5,001 cc)), utilizing the 350's crankshaft throw. This new engine family would provide better gas economy than the 350, share its basic architecture and many parts with the 350 (thus reducing production costs), and provide customers with more horsepower/torque than Chevrolet's 1970s-era inline 6 and V6 engines. During the early 1980s, when GM was streamlining their engine lineups, the Chevrolet 305 would rise to prominence as General Motors' "corporate" engine, signified by being the standard (and often only) V8 in many GM vehicles. Through much of the 80's, the 305 became General Motors' most common V8, followed closely by Oldsmobile's robust 307. The Chevrolet 305 also became the standard V8 in GM's C/K truck series, and was even used in the Corvette for one year in 1980.

Crankshafts used with the 305 had the same casting number as the 350 with one discernable difference - the 305 crank is lighter in weight to compensate for engine balancing. (The counterweights are smaller, which makes it unsuitable for use in a 350 where metal would have to be welded back on.) The medium journal 305, like its big-brother 350, would be further developed in the 1990s, although with a reduced 3.00" stroke (using 5.94" connecting rods), into the "Generation II SBC" GM LT-Series engine L99 263.

Introduced in 1976 models, it had a displacement of 305 cu in (5.0 L) The 305 was used in the following cars:

  • 1976–1992 Chevrolet Camaro
  • 1977–1993 Chevrolet Caprice (includes Impala)
  • 1980 Chevrolet Corvette (California only)
  • 1976–1988 Chevrolet Malibu, Chevrolet El Camino/GMC Caballero, and Chevrolet Monte Carlo
  • 1976–1979 Chevrolet Monza
  • 1976–1979 Chevrolet Nova (also GM X-body clones after 1976)
  • 1977–2003 Chevrolet/GMC Trucks, SUVs, Vans
  • 1978–1987 Buick Regal (rare after 1980)
  • 1975–1979 Buick Skylark
  • 1991–1992 Cadillac Brougham
  • 1977–1981 Checker Marathon
  • 1991–1992 Oldsmobile Custom Cruiser
  • 1977 Oldsmobile Omega
  • 1978–1980 Oldsmobile Cutlass (U.S. market only, Canadian market 1978–1987)
  • 1977–1981 Pontiac Catalina (B-body)
  • 1977–1981 Pontiac Bonneville (B-body)
  • 1982–1986 Pontiac Bonneville (G-body)
  • 1977–1992 Pontiac Firebird
  • 1981–1987 Pontiac Grand Prix
  • 1978–1981 Pontiac Grand LeMans (A/G-body, includes Grand Am)
  • 1982–1986 Pontiac Parisienne (B-body)
  • 1982–1986 Pontiac Parisienne Safari (B-body wagon)
  • 1979 Pontiac Sunbird

The Chevrolet 305 is a reliable, fuel efficient V8, easily capable of 200,000 miles, if maintained. From 1976 onward into the early 1980s, these engines were also prone to wearing out their camshaft lobes very prematurely due to a combination of improper manufacturing and reduced/poor quality controls (a result of GM cost-cutting measures). The 305 is sometimes dismissed in performance circles because of its "lack of power", its small bore size, and difficulty flowing large volumes of air at higher rpms; however, two variants of the '83-'92 305 were notable performers, especially when in comparison to most of the other "performance engines" of that time: the '83 -'88 L69 "High Output 5.0L" (only used in late '83 -early '86 F-body/ late '83 -'88 Monte Carlo SS) and the '85 -'92 LB9 "Tuned Port Injection 5.0L" (F-body only).

After 1993, its usage was limited to light trucks and SUVs until the 2000 model year (vans and commercial vehicles until 2003). The 305 was sold as a crate motor under the Mr. Goodwrench brand as a replacement motor and as a boat engine for Mercury Marine until late 2014 when it was discontinued. The cylinder block is still in production by GM (part number 10243869) for Sprint Car Spec Racing.

Year hp (kW) lb•ft (N•m)
1976 140 (104) 250 (339) w/2bbl.
1977 145 (108) 245 (332) w/2bbl.
1978 140 (104) 240 (325) w/2bbl.
1978 160 (119) 235 (319) w/4bbl.
1979 130 (97) 245 (332) w/2bbl.
1979[a] 125 (93) 235 (319) w/2bbl.
1980 155 (116) 240 (325) w/4bbl.
1981 150 (112) 240 (325) w/4bbl

a Note: California Emissions

LG3

Years:1976–1980

This variant used a Rochester 2GC from 1976 to 78. In 1979, the more fuel-efficient Rochester Dual-Jet 2bbl carburetor replaced the older 2GC. This change also resulted in a drop in the horsepower rating to 130 hp (125 for California emissions cars). All years had an 8.5:1 compression ratio.

LG4

Years: 1980–1988*

The LG4 produced 150 hp (112 kW)-170 hp (127 kW) and 240 lb·ft (325 N·m)-250 lb·ft (339 N·m). Introduced in 1978, the LG4 was essentially an LG3 with the addition of a 4-bbl carburetor. The engine saw a series of gradual improvements, increasing reliability, mpg, and power output through its production run. In 1981 (1980 for California models) Chevrolet added GM's new "Computer Command Control" (CCC) engine management system to the LG4 engines (except Canadian models). The CCC system included the electronic Rochester 4-bbl E4ME Quadra-Jet, with computer-adjusted fuel metering on the primary venturis and a throttle position sensor allowing the CCC to calculate engine load. In the ignition system, CCC was fully responsible for the timing curve; mechanical and vacuum advances were eliminated from the distributor. The more precise spark timing provided by the CCC made possible a series of increases in compression ratio from a pre-CCC 8.4:1, to 8.6:1, to a knock-sensor-assisted 9.5:1, all while still only requiring 87 AKI regular unleaded fuel.

In 1983, Chevrolet replaced the cast iron intake with an aluminum version and utilized either 14014416 ("416") or 14022601("601") heads with int: 1.84/ exh: 1.50 valves, 58cc chambers, 178cc runners. For 1985, the 4-valve-relief, flat top pistons from the L69 were added to the LG4 which resulted in another increase in compression. Also added was a knock sensor to allow the "CCC" engine management system to compensate for the increase in compression and a more aggressive spark timing map in the ECM. As a result, power increased for the 1985 models to 165 hp (123 kW) from the 150 hp (112 kW) rating in 1984. For 1986, Chevrolet changed over to a 1 piece rear main seal engine block design to minimize leaks and warranty claims, however some early '86 blocks retained a 2 piece rear main seal.

For 1987, Chevrolet once again made some revisions to increase overall reliability, many of them borrowed from the TBI L03, which was to replace the LG4. The coil-in-cap HEI distributor was retired, and an all-new electronic distributor design was used. The intake manifold to head bolt pattern was redesigned to improve gasket integrity - four of the center intake manifold bolts were drilled at 72 degrees instead of 90 degrees for the cast iron cylinder heads. Changes to the valve covers were also made. "ribbing" was added to the top of the valve covers to increase surface area, acting as a heat sink. To improve intake gasket sealing, the mounting bolts were relocated to the valve cover centerline, placing all sealing pressure evenly upon the mounting flange perimeter... thus these became known as "centerbolt valve covers", first introduced in 1985 on the LB4 4.3L V6 and the Corvette a year earlier (the aluminum cylinder heads used with the Vette were the first to have the centerbolt valve covers). Another improvement was utilization of a hydraulic lifter/roller camshaft on most '87 LG4's. Some early engines have lifter retainer provisions, but utilize the older, non-roller camshaft. 1987 would also be the last year for the LG4 production, however a run of LG4 engines was made to supplement the carry-over production for the 1988 Monte Carlo and the 1988 Chevrolet Caprice.

LU5

Years: 1982 – late-1983

The LU5 "Crossfire EFI 5.0L" featured a dual Throttle Body Injection set-up, based upon the original "Crossram Intake" supplied by Chevrolet for the 1969 Camaro Z28. Unlike, the original '69 version, Chevrolet did not place it in the trunk for owners to install. The system utilized a special version of GM's still-new "CCC" engine management system. Fuel was supplied by the two TBI units, set diagonally apart from each other, atop the unique, aluminum intake manifold. Unfortunately, the system was placed atop the basic LG4 and lacked any significant performance capability. The engine was originally planned for the long-awaited '82 Camaro Z28, however due to a last-minute GM-mandated cancellation of Pontiac's 301 V8 production & Turbo 4.9L Project (T301), the Crossfire 305 was made available in the '82 Trans Am. A 350 cubic inch version was also used in the Corvette. Being fairly early into GM's electronic engine management development and electronic fuel injection programs, few dealerships had the technology, equipment, or properly trained mechanics capable of dealing with these engines. Compounding these problems were widely varying fuel quality standards, production issues, poor quality control by GM, & owners who tinkered with a system they did not understand. In a very short time, these engines obtained the notorious nickname; "Ceasefire Engine". Today, owners with these engines note that they are fairly reliable, and that a significant upgrade can be made by simply using the L69/LB9 TPI/L98 TPI exhaust manifolds/ exhaust systems... When combined with performance-built stock 305 heads w/larger valves or aftermarket heads, plus a camshaft upgrade, these engines can perform surprisingly well. Thanks mostly to a somewhat cult-like following, a number of aftermarket performance parts are also available through Crossfire-specialized manufacturers.

L69

Years: late-1983 – 1988

The L69 "High Output 5.0L" was released late into the 1983 model year. It was optional only in the "Firebird Trans Am", "Camaro Z28", and "IROC-Z", and was standard in the revived "Monte Carlo Super Sport". (no other GM models were available with this engine)

The L69 features a compression ratio of 9.5:1, 4-relief flat top pistons, a unique and relatively aggressive stock camshaft, GM PN: 14088843* hydraulic flat tappet - duration at 0.050": 202/206 - max lift: 0.403/0.415 - 115 - idle: 650 rpm... *(not a camshaft taken from another Chevrolet engine). It also utilizes a performance-tuned "CCC" ECM/PROM, a knock sensor, a performance-tuned E4ME 750CFM Rochester Quadra-Jet 4 barrel carburetor, and a special, free-flowing exhaust system with large diameter exhaust manifolds, Y-Pipe, catalytic converter, and exhaust system. (The L69 F Body exhaust system components would be revised slightly and used again on the later LB9 305 and L98 350 TPI engines.) Additionally, the engines came equipped with a functional cold air induction hood on the 1983-1984 Trans Am H.O., a dual snorkel air cleaner assembly on the 1983-1986 Camaro Z28/IROC-Z H.O., and 1985-1986 Trans Am H.O., and a large, single snorkel, on the 1983-1988 Monte Carlo SS (also, rare optional dual snorkel in 1987-1988), an aluminum intake manifold, high stall torque converter in the Monte SS and 1984 F-Body, or a lightweight flywheel on T-5 eqipped F-Body's, and all F-Bodies utilized 3.73 axle gears (3.42 Standard in 1984 F-Body/ THM700R4/optional w/3.73:1). The Monte Carlo SS featured a special HD version of the THM200-4R in 86-88 also used in the Buick Turbo Regal/GN and Olds Hurst/Olds-442 along with 3.73 axle gears. The Th450 was used in the Monte Carlo SS from 83-85 and had 3.42 axle gears.

The L69 engine produced 190 hp (142 kW) at 4800 and 240 lb·ft (325 N·m) of torque at 3200 rpm. in the F-Body and was rated at 180 hp in the Monte SS.

LE9

Years: 1981–1986

The LE9 5.0 L (305 cu in) was a truck/van/car version 4BBL 650CFM that also had a 9.5:1 compression ratio, the LM1 cam and 14010201 casting heads featuring 1.84/1.50" valves and 53 cc (3.2 cu in) chambers. The engine produced 165 hp (123 kW) at 4,400 and 240 lb·ft (325 N·m) at 2,000 rpm.

LB9

Years: 1985–1992

The LB9 "Tuned Port Injection 5.0L" was introduced in 1985. At its core was the stout L69 shortblock and it utilized the same aggressive L69 camshaft profile. The induction system was unlike any system used previously by GM. It featured a large plenum made of cast aluminum, with individual runners made of tubular aluminum, feeding air to each cylinder. And each cylinder had its own fuel injector fed by a fuel rail mounted above each bank. In 1985, this engine was optional only in the "Camaro IROC-Z" and "Trans Am" equipped with the WS6 performance suspension. In the Corvette, a 350ci version of this engine, the L98, was released...it would be two years before the L98 would be offered in the F-Body. The LB9 was also available in the '87-92 GTA and Firebird Formula. 215 hp (160 kW) and 275 lb·ft (373 N·m) and varied between 190 hp (142 kW)-230 hp (172 kW) (with 275 lb·ft (373 N·m)-300 lb·ft (407 N·m) of torque) over the years offered.

L03

Years: 1987–95

The L03 produced 170 hp at 4,400 rpm and 255 lb·ft (346 N·m) of torque at 2,400 rpm in 1993–1995 GM trucks. This engine used the TBI throttle-body fuel injection. It featured "swirl port" heads and served as the base V8 engine in all C/K 1500 Series GMC/Chevrolet Trucks/Vans. (The LB4 4.3L V6 was the standard engine in these models.)

L30

Years: 1996-2003

The Vortec 5000 L30 is a V8 truck engine. Displacement is 5,013 cc, (305.9 cubic inches). Bore is 95 mm (3.7 in), stroke is 88.4 mm (3.5 in). The compression ratio is 9.1:1.[14] It is a based on the Generation I small-block from Chevrolet. It was replaced by the 4.8 L Vortec 4800 LR4 for the 2003 full-size vans. In C/K truck configuration it produces 230 hp (172 kW) net flywheel at 4,600 rpm and 285 lb·ft (386 N·m) net flywheel torque at 2,800 rpm. In van configuration it produces 220 hp (164 kW) net flywheel at 4,600 rpm and 290 lb·ft (393 N·m) net flywheel torque at 2,800 rpm. The engine uses a hydraulic roller cam and high flowing, fast burn style vortec heads. Differences include bore and stroke, intake valve size, and smaller combustion chambers. L30 applications:

  • Chevrolet Express/GMC Savana
  • General Motors C/K full-size trucks

262

L99

The L99 4.3 L (263.1 in3) V8 shared a 3.736 inches (94.9 mm) cylinder bore with the 305 in3 but had a 3 inches (76 mm) stroke compared to the 3.48 inches (88 mm) stroke of the 305 in3. The pistons used in the 4.3 L V8 were the same as the ones used in the Vortec 5000, but 5.94 inches (151 mm) connecting rods were used to compensate for the shorter stroke. It was designated by the RPO code L99, and was introduced in the 1994 model year. This was the base engine used in 1994-1996 Chevrolet Caprice Sedans, the 9C1 police package sedans and the 1A2 special service station wagons. The L99 was not available in other vehicles.

The L99 featured updated Generation II block architecture and is visually identical to the larger 5.7 L LT1 Generation II V8. Like the LT1, it features sequential fuel injection, reverse-flow cooling, and an optical ignition pickup. Output is 200 hp (150 kW) and 245 lb·ft (332 N·m). Due to its smaller displacement, the L99 provided higher EPA fuel economy ratings than the 5.7 L LT1. The L99 was produced for the 1994-1996 model years.

3.50 in bore family (1979–1982)

267

The 267 was introduced in 1979 for GM F-Body (Camaro), G-bodies (Chevrolet Monte Carlo, El Camino, and Malibu Classic) and also used on GM B-body cars (Impala and Caprice models). The 267.8 cu in (4,389 cc) engine had the 350's crankshaft stroke of 3.48" and the smallest bore of any small-block, 3.500 in (88.9 x 88.4 mm), shared with the 200 V6 introduced a year earlier.

It was only available with a Rochester Dualjet 210 – effectively a Rochester Quadrajet with no rear barrels. After 1980, electronic feedback carburetion was used on the 267. The 267 also saw use in 1980 to 1982 Checker Marathons.[15]

While similar in displacement to the other 4.3L(265)–4.4L(267) V8 engines produced by General Motors (including the Oldsmobile 260 and Pontiac 265), the small bore 267 shared no parts with the other engines and was phased out after the 1982 model year due to inability to conform to emission standards. Chevrolet vehicles eventually used the 305 cu in (5.0 L) as their base V8 engine.

Major changes

The original design of the small block remained remarkably unchanged for its production run, which began in 1955 and ended, in passenger vehicles, in 2003. The engine is still being built today for many aftermarket applications, both to replace worn-out older engines and also by many builders as high-performance applications. The principal changes to it over the years include:

  • 1956 – Full-flow oil filtration was introduced, using a paper element filter in a canister that was mounted to a boss that was added to the left rear cylinder block casting and machined for this purpose.
  • 1957 – The displacement of the base V8 continued at 265 cubic inches, but optional V8 engines were introduced with a displacement of 283 cubic inches.
  • 1958 – Bosses for side motor mounts were added to the block casting, utilized for production mounts for this and all future model years. However, the features for front motor mounts as used in 1955–1957 remained part of the block casting in this and future years. The 265-cubic-inch version of the engine was discontinued. Also, the cylinder head valve cover mounting bolt holes were changed from the top row staggered (relative to the bottom row of bolts) to the "straight-across" pattern that remained the way of identifying the early heads from the newer ones with a valve cover design which lasted until the 1987 center-bolt-style covers.
  • 1962 – The block's cylinder wall casting was revised to allow four-inch bores, and the 327-cubic-inch version of the engine, using this bore diameter and increased stroke, was introduced.
  • 1967 - The oil filter mounting now came from the factory with an adapter and machining to allow the use of spin-on filters; canister mounting was possible by removing the adapter.
  • 1968 – The main-journal diameter was increased from 2.30" (small) to 2.45" (medium), and the connecting-rod journal diameter was increased to 2.10" from 2.00". This allowed the use of cast-iron crankshafts; the previous crankshafts were made of forged steel, which was more expensive. The rod bolts were changed from 11/32" diameter to 3/8". The oil-fill location was moved from a tube on the front of the intake manifold to a cap on the left- or right-side valve cover, depending upon the application.
  • 1970 - The "400" is introduced in September 1969 for the 1970 model year, with a bore of 4.125" and a stroke of 3.75". This engine introduced the "large-journal" crankshaft with a main journal size of 2.65" and rod bearing journals of 2.10". This engine also introduced "Siamese bores" to the Chevrolet small-block line, requiring "steam holes" in the cylinder heads and head gaskets, which were used to prevent hot spots and subsequent overheating. The connecting rods, due to the long stroke, are also shorter at 5.565", differing from the 5.7" length of all other Generation I small-block connecting rods.
  • 1986 – The rear main seal was changed from a 2-piece rubber design to a 1-piece rubber design that used a mounting appliance to hold it in place. This necessitated a change in the flywheel/flexplate bolt pattern as well as requiring an externally balanced flexplate/flywheel.
  • 1987 – The valve cover surfaces were changed so that the mounting lip was raised and the bolt location was moved from 4 bolts on the perimeter to 4 bolts along the centerline of the valve covers (this design debuted on the Corvette in 1986, and the Chevrolet 4.3L 90 degree V6 the year before). Also changed were the mounting angles of the two center bolts on each side of the intake manifold (from 90 to 73 degrees), and the lifter bosses were increased in height to accept roller lifters; the aluminum-alloy heads for use on the Corvette engines retained the non-angled bolts. Also, all carburetors(except some 1987-89 F-body and B-body models, also the 30 and 3500 model 1-ton trucks through 1989 with either the M-code 350 or W-code 454 engines, in which all retained the 4bbl rochester E4ME carbs) were replaced by TBI (throttle-body injection) fuel injection.
  • 1996 – This was the last change for the Generation I engine, which continued through the end of the production run in 2003; all 1997–2003 Generation I engines were "Vortec" truck engines. The cylinder heads were redesigned, using improved ports and combustion chambers similar to those in the Generation II LT1, resulting in significant power increases. The intake manifold bolt pattern was also changed to four bolts per cylinder head instead of the "traditional" five bolts. The cylinder block timing cover lip was thickened for use with the plastic timing cover (redesigned for use with a crankshaft position sensor with integrated dowel pins - cylinder blocks for 1996+ do not have dowel pins in the timing cover flange) held with 8 bolts and the water pump bypass hole on the RH deck and below the water pump passage undrilled. Also the fuel pump boss is still present but undrilled (which dates back to the 1992 model year).

Details

Chevrolet Generation I V8 Small Block Engine Table

note 1: depending upon vehicle application; horsepower, torque, and fuel requirements will vary.

Gen I Years Engine option code (VIN identifier) Power (hp) Torque (lb.-ft.) Displacement (c.i.) Fuel (octane) Bore x Stroke (in) Compression ratio Block & heads (iron or aluminum) Block features
I 1996-02 L30 (M) 220@4600 290@2800 305 3.7 x 3.5 9.1:1 Iron Truck/van only
I 1987-95 L03 (E/H) 170@4400 255@2400 305 3.7 x 3.5 9.1:1 Iron TBI; passenger car used roller cam
I 1988-96 L05 (K) 210@4400 300@2800 350 4.0 x 3.48 9.3:1 Iron TBI; 9C1 optioned Caprice and F-bodies had hydraulic roller cam
I 1978-88 LG4 (F/H) 150-170@4600 240-250@2800 305 3.7 x 3.5 8.6:1 Iron 4bbl Quadrajet
I 1981-86 LE9 (F) 165@4400 240@2000 305 3.7 x 3.5 9.5:1 Iron Truck/Van only - electronic spark control module used
I 1982-83 LU5 305 3.7 x 3.5  ?:1 Iron "Crossfire EFI 5.0L"
I 1967-80 L48 (K) 165-195 380 350 4.0 x 3.48 8.25-10.5:1 Iron
I 1969-70 L46 350 350 93req 4.0 x 3.48 11.0:1 Iron Corvette only
I 1969-76 L65 145 350 4.0 x 3.48 Iron 2bbl
I 1969-88 LM1 (L) 155-175 350 4.0 x 3.48 Iron 4bbl Rochester Quadrajet (4MV, M4MC, E4M); retail option until 1981 when last used with the Camaro Z28; post-1980 use of the LM1 was for 9C1-optioned B (Caprice, Impala) and G-bodies (Malibu)
I 1970-74 ZQ3 190-300 270-300 350 4.0 x 3.48 8.5-10.25:1 Iron 4bbl, Corvette
I 1970-72 LT1 330-370@6000 270-300@4000 350 4.0 x 3.48 9.1:1 Iron TBI
II 1992-97 LT1 (P) 260-305@4800-5200 325-340@2400-3400 350 91 OCTANE 4.0 x 3.48 10.4:1 Iron (Aluminum FOR F and Y Bodies) Reverse Flow Heads
I 1973-80 L82 205-250 255-285 350 4.0 x 3.48 9:1 Iron 4bbl Rochester Quadrajet; flat top pistons with a D-shaped relief cut for valve clearance
I 1981 L81 190 280 350 4.0 x 3.48 8.2:1 Iron TBI
I 1970-86 LS9 (L) 165@3800 275@1600 350 4.0 x 3.48 8.2:1 Iron 4bbl, truck
I 1981-86 LT9 (M) 160@3800 250@2800 350 4.0 x 3.48 8.3:1 Iron 4bbl, truck
I 1982-84 L83 200-205 285-290 350 4.0 x 3.48 9.0:1 Iron CrossFire
I 1985-92 L98 (8) 225-250@4000 330-345@3200 350 4.0 x 3.48 9.5-10:1 Iron/Aluminum (some) TPI
I 1996-02 L31 (R) 255-350@4600 330-350@2800 350 4.0 x 3.48 Iron truck, Vortec
I 1970-80 245-265 400 4.125 x 3.75 Iron 70-72 4bolt main, 73-80 2bolt main
I 1975-76 110 133@3600 262 3.736 x 3.0 Iron Nova and Monza only; 2bbl Rochester 2GC carburetor
I 1994-96 L99 (W) 200 245 262 3.736 x 3.0 Iron reverse cooling, Caprice, special ops, police vehicles
I 1983-88 L69 (G) 180-190@4800 240@3200 305 3.736 x 3.48 9.5:1 Iron H.O., Firebird/Camaro, Monte Carlo SS only
I 1985-92 LB9 (F) 190-230 275-300 305 3.7 x 3.5 Iron TPI, Firebird/Camaro only
I 1976-80 LG3 (U) 170@4400 255@2400 305 3.736 x 3.48 8.5:1 Iron 2bbl

Generation II GM small-block (1992–1997)

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General Motors' Generation II LT1 is a small block V8 engine. Making its debut in the 1992 Chevrolet Corvette, the new LT1 sought to draw upon the heritage of the 1970 Chevrolet LT-1.

A significant improvement over the original Generation I V8 is the Generation II LT1's "reverse cooling" system, allowing coolant to start at the heads and flow down through the block. This keeps the heads cooler, affording greater power through a higher compression ratio and greater spark advance at the same time it maintains higher and more consistent cylinder temperatures.

Some parts from the Generation II are interchangeable with the Generation I one-piece rear main seal engine. The interchangeable parts include the rotating assembly (crank shaft, pistons, connecting rods, and flywheel/flexplate) and valvetrain assembly (not including timing set, which includes a gear to drive the water pump). The LT1 uses a new engine block, cylinder head, timing cover, water pump, intake manifold and accessory brackets. The harmonic damper also does not interchange; it is a unique damper/pulley assembly. Engine mounts and bell housing bolt pattern remain the same, permitting a newer engine to be readily swapped into an older vehicle.

4.00 in bore blocks

5.7 L
LT1
GM LT1 from a 1993 Chevrolet Camaro Z28.

In 1992, GM created a new-generation small-block engine called the "LT1 350", not to be confused with the high-output Generation I LT-1 of the 1970s. It displaced 5.7 L (350 cu in), and was a 2-valve pushrod design. The LT1 used a reverse-flow cooling system which cooled the cylinder heads first, maintaining lower combustion chamber temperatures and allowing the engine to run at a higher compression than its immediate predecessors.

This engine was used in:

  • Y-body:
    • 1992–1996 Chevrolet Corvette C4
  • F-body:
    • 1993–1997 Chevrolet Camaro Z28, B4C and SS
    • 1993–1997 Pontiac Firebird Formula and Trans Am
  • B-body:
    • 1994-1996 Buick Roadmaster
    • 1994–1996 Chevrolet Caprice
    • 1994–1996 Chevrolet Caprice Police Package
    • 1994–1996 Chevrolet Impala SS
    • 1994–1996 Chevrolet Caprice Wagon
    • 1994–1996 Buick Roadmaster Wagon
  • D-body:
    • 1994–1996 Cadillac Fleetwood

There were a few different versions of the LT1. All feature a cast iron block, with aluminum heads in the Y and F bodies, and cast iron heads in the B and D bodies. Corvette blocks had four-bolt main caps, while most other blocks were two-bolt main caps. Block castings remained the same between 2 and 4 bolt mains.

The 92–93 LT1s used speed density fuel management, batch-fire fuel injection and a dedicated Engine Control Module (ECM). In 94 the LT1 switched to a mass airflow sensor and sequential port injection. A new, more capable computer controlled the transmission as well as the engine and got a new name: Powertrain Control Module (PCM). Where the EC5M held its calibration information in a replaceable PROM chip, the 94-95 OBD1 PCMs are reprogrammable through the diagnostic port.

The early Optispark distributor had durability problems and a revised version was introduced with vacuum vents to remove moisture and ozone on the 1994 B-Bodies and in 1995 on the Y and F-Bodies; the vacuum vents can be added onto earlier distributors.[16] 1996 saw major revisions for OBD-II: a second catalytic converter on the F-body cars and rear oxygen sensors to monitor catalyst efficiency. Some OBD-II features had been added to the Corvette starting in 1994 for testing purposes.[citation needed] The 1997 model year Camaro and Firebird were the last year for this engine in a GM production car before it was replaced by the LS1, which was already in the Corvette for 1997.

The 1992 LT1 in the Y-body was factory rated at 300 hp (220 kW) and 330 lb·ft (447 N·m). 96 LT1 Y-bodies were rated at 300 hp (220 kW) and 340 lb·ft (461 N·m). The 93–95 F-bodies were rated at 275 horsepower (205 kW) and 325 lb·ft (441 N·m), while the 96–97 cars were rated at 285 horsepower (213 kW) and 335 lb·ft (454 N·m). The 96–97 WS6 and SS F-bodies were rated at 305 hp (227 kW). The 94–96 B and D-body version was rated at 260 horsepower (190 kW) and 330 lb·ft (447 N·m).

LT4

The LT4 was a special high-performance version of the new-generation LT1. With the addition of a slightly more aggressive camshaft profile, 1.6:1 roller aluminum rocker arms, high-flow intake manifold (painted red) with extra material above the port available to allow port matching to the raised port LT4 cylinder heads, it was rated at 330 horsepower (250 kW) and 340 lb·ft (461 N·m). It was introduced in the 1996 model year, for the last year of the C4 Corvette, and came standard on all manual transmission (ZF 6-speed equipped) C4 Corvettes. The engine was passed down to special versions of the Camaro and Firebird the next model year.

The LT4 was available on the following vehicles:

  • 1996 Chevrolet Corvette when equipped with 6-speed manual transmission (includes all Grand Sports) (Production: 6,359)
  • 1997 Chevrolet Camaro SLP/LT4 SS 6-speed (Production: 100 for the U.S., 6 for Canada. There were 2 prototypes)
  • 1997 Pontiac Firebird SLP/LT4 Firehawk 6-speed (Production: 29)

All 135 production engines for the Firehawks and Camaro SS were completely disassembled, balanced, blueprinted and honed with stress plates. One in 5 engines was tested on a Superflow engine dyno and every car was tested on a chassis dyno in addition to performing a short 6-mile (10 km) road test.

3.736 in bore blocks

4.3 L
L99

A 260 in3 (4.3 L) was based on a 305 in3 with updated block architecture to be Generation II and a reduced 3 inches (76 mm) stroke. It was designated the L99, and was introduced in 1994 for the Chevrolet Caprice. It was externally identical to the LT1, but the bore was decreased to 3.736 inches (94.9 mm) and the stroke to 3 inches (76 mm) giving it a displacement of 263 in3. The pistons used in the L99 were the same as the ones used in the Vortec 5000, but 5.94 inches (151 mm) connecting rods were used to compensate for the shorter stroke. This was the base engine used on all 1994-1996 Chevrolet Caprice Sedans, including the Police Package vehicles.

Like the LT1, it features sequential fuel injection, reverse-flow cooling, and an optical ignition pickup. Output is 200 hp (150 kW) and 245 lb·ft (332 N·m). Due to its smaller displacement, it provides better fuel economy than the 5.7 L LT1, but at reduced horsepower & torque levels.

3.90 in bore blocks

5.7 L
LT5
A GM LT5 engine

For model year 1990, Chevrolet released the Corvette ZR-1 with the radical Lotus Engineering-designed double overhead cam LT5 engine. Engineered in the UK but produced and assembled in Stillwater Oklahoma by specialty engine builder Mercury Marine, the all-aluminum LT5 shared only the 4.4 inch bore spacing with any previous LT engine. It does not have reverse cooling and is generally not considered a small block Chevy.

Used only in Corvettes,[17] the LT5 was the work of a team headed by Design manager David Whitehead, and was hand built by one headed by project engineer Terry D. Stinson.[18] It displaced 5.7 L (349 cu in) and had a 3.9 by 3.66 in (99 by 93 mm) bore and stroke instead of the usual 4 by 3.48 in (102 by 88 mm) and featured Lotus-designed 32-valve DOHC heads rather than the usual Chevrolet 16-Valve OHV Heads. The preproduction LT5 initially produced 385 horsepower (287 kW), but was reduced to 375 horsepower (280 kW) and 370 lb·ft (502 N·m) for the 1990-1992 Corvette ZR-1. The power ratings jumped to 405 horsepower (302 kW) and 385 lb·ft (522 N·m) from 1993 until its final year in 1995, thanks to cam timing changes and improvements to the engine porting. 1993 also added 4-bolt main bearing caps and an exhaust gas recirculation system.

A second generation of the LT5 was in the testing phase as early as 1993. What little information survived showed that it would have utilized a dual plenum system similar to the first generation Dodge Viper as well as variable valve timing. The next generation LT5 was set to produce between 450 horsepower (340 kW) and 475 horsepower (354 kW). Unfortunately, the cost to produce the LT5 along with its weight, dimensions (would not fit the C5 pilot cars without extensive modifications) and internal GM politics over using an engine that was not designed and built in house killed the LT5 after six years of production. GM canceled the ZR-1 option beginning model year 1993. Engines that were to be installed in the as yet unbuilt ZR-1's were sealed and crated for long term storage. After they were built at the Mercruiser plant in Stillwater, Oklahoma they were shipped to Bowling Green, Kentucky and stored in the Corvette assembly plant until the 1994 and 1995 ZR-1s went down the assembly line. A total of 6939 were produced.[19] The LT5 however wasn't an evolutionary dead end. Despite being discontinued, a new class of premium V8s for Cadillac and eventually Oldsmobile, the dual overhead cam V8 Northstar and its derivatives, drew heavily from the LT5's design and lessons learned from its production.[20] GM also took lessons learned from producing a completely aluminum engine and applied them to the new LS series of engines.

The LT5 was available on the following vehicles:

  • 1990-1995 Chevrolet Corvette C4 ZR-1 equipped with 6-speed manual transmission (Production: 6,939). Although the LT5 was never used in another production GM vehicle, it did make its way into several Corvette concepts, race cars and even into a limited run of the Lotus Elise GT1.

LT6 and LT7

The LT6 and LT7 are not part of the LT family. See Oldsmobile Diesel engine for more information.

See also

  • General Motors 90° V6 engine
  • Buick V8 engine
  • Cadillac V8 engine
  • Oldsmobile V8 engine
  • Pontiac V8 engine
  • Holden V8 engine
  • GMC V8 engine
  • GMC V6 engine
  • 1917-1918 Chevrolet Series D V8
  • Chevrolet Big-Block engine
  • GM LT engine – Generation II small block
  • GM LS engine – Generation III/IV small block
  • List of GM engines

References

  • McGuire, Bill (June 20, 2005). "Horsepower Nation: Chevrolet's small-block V8 celebrates its 50th birthday". AutoWeek. Retrieved June 15, 2005. 
  1. ^ a b Sherman, Don (1 January 2000). "The 10 Best Engines of the 20th Century". Ward's AutoWorld. Retrieved 1 October 2016. 
  2. ^ Borroz, Tony (22 September 2011). "https://www.wired.com/2011/08/chevrolets-mouse-that-roared/". Wired Magazine. Retrieved 1 October 2016.  External link in |title= (help)
  3. ^ a b "Chevy 265-cid V8 Engine". Consumer Guide. Retrieved 1 October 2016. 
  4. ^ a b c Udy, Jason (3 November 2011). "Small-Block Chevy V8 through the Years". MotorTrend. Retrieved 1 October 2011. 
  5. ^ Flory, J. "Kelly", Jr. American Cars 1960–1972 (Jefferson, NC: McFarland & Coy, 2004), p.341.
  6. ^ Braunschweig, Robert; et al., eds. (March 11, 1971). "Automobil Revue '71" (in German and French). 66. Berne, Switzerland: Hallwag SA: 242. 
  7. ^ Flory, p.411.
  8. ^ a b c d e Gunnell, John. Standard catalog of Corvette, 1953-2005. Krause Publications, 2004
  9. ^ a b c Gunnell, John. Standard Catalog of Corvette, 1953-2005. Krause Publications, 2004
  10. ^ Gunnell, John, 360 bhp with the Camaro's 'log' manifold exhaust system and points ignition. Standard Catalog of Corvette, 1953-2005. Krause Publications, 2004
  11. ^ "Chevy Truck Engine Specification a RPO Codes, Horsepower, Displacement, Torque Ratings, - Chuck's Chevy Truck Pages.com". Chuckschevytruckpages.com. Retrieved 2013-11-22. 
  12. ^ a b "LT9 engine - ChevyTalk -The Social Network for Chevy Fans". ChevyTalk. Retrieved 2013-11-22. 
  13. ^ Chevrolet Pickups 1973-1998: How To Identify Select And Restore Collector ... - Google Books. Books.google.com. 2008-02-23. Retrieved 2013-11-22.  line feed character in |title= at position 87 (help)
  14. ^ "information on the Chevrolet C1500 w/ L30 engine". Automotive.com. Retrieved 2012-01-25. 
  15. ^ Standard Catalog of Independents, pp. 41-42
  16. ^ Corvette Fever- Fixing An Opti-Spark Distributor Without Reaching For A Hammer. Andy Bolig
  17. ^ "LT5 Engine Specs". Zr1netregistry.com. 2012-02-28. Archived from the original on July 4, 2012. Retrieved 2012-06-04.  // via archive.org
  18. ^ "Orbital Appoints Terry Stinson as Chief Executive Officer and Managing Director". Reuters. 2008-05-20. Retrieved 2012-06-04. 
  19. ^ "ZR-1 FAQ". Zr1netregistry.com. Retrieved 2012-06-04. 
  20. ^ http://www.cadillacfaq.com/faq/answers/pdf/ls6-article.pdf

External links

Wikimedia Commons has media related to Chevrolet small-block engine.
  • Mortec: Small-Block Engine Enthusiasts
  • [https://www.youtube.com/watch?v=BfTw3ChsmHM/ Video : First start up SBC engine (& zoomies flames)
  • Video : Let's see Chevy first start up, and what NOT to do ! ("Dark" humor)

en.wikipedia.org

Chevrolet Big-Block engine

The Chevrolet big block is a series of large displacement V8 engines that were developed in the USA during the 1950s and 1960s. As American automobiles grew in size and weight following the Second World War the engines powering them had to keep pace. Chevrolet had introduced their popular GM Small-Block engine in 1955 but needed something larger to power their medium duty trucks and the heavier cars that were on the drawing board. The decision was made by Chevrolet to develop an all-new design for large-displacement use. This engine family had two generations, the "W" series, and the Mark IV series.

Generation 1: "W" Series

The first ever production big block V8 Chevrolet engine was the "W" series, released in 1958 for passenger car and truck use. This engine was an overhead valve design, with offset valves and unique scalloped rocker covers, giving it a distinctive appearance. The "W" series was produced from 1958 to 1965, with three displacements offered: 348 cubic inches (5.7 L), available from 1958 to 1961 in cars and through 1964 in trucks; 409 cubic inches (6.7 L), available from 1961 to 1965; and 427 cubic inches (7.0 L), available only in 1963.

As was the norm at the time, the "W" engine was of cast iron construction. The block had 4.84-inch (123 mm) bore centers, two-bolt main bearing caps, a "side oiling" lubrication system (main oil gallery located low on the driver's side of the crankcase) with full flow oil filter, and interchangeable cylinder heads. Heads used on the high performance 409 and 427 engines had larger ports and valves than those used on the 348 and the base 409 passenger car and truck engines, but externally were identical to the standard units. One minor difference between the 348 and 409/427 was the location of the engine oil dipstick: it was on the driver's side on the former and passenger's side on the latter. No satisfactory explanation was ever presented for why this seemingly useless change was made. However, it was a fairly reliable way to differentiate between the smaller and larger versions of the engine.

As with the 265 and 283 cubic inch small block engines, the "W" engine valve gear consisted of tubular steel push rods operating stud-mounted, stamped steel rocker arms. The push rods also acted as a conduit for oil flow to the valve gear. Due to the relatively low mass of the valve train, mechanical lifter versions of the "W" engine were capable of operating at speeds well beyond 6000 Revolutions per minute.

Unlike many of its contemporaries, the "W" combustion chamber was in the upper part of the cylinder, not the head, the latter which only had tiny recesses for the valves. This arrangement was achieved by combining the use of a cylinder head deck that was not perpendicular to the bore with a crowned piston, a novel concept in American production engines of the day. As the piston approached Top dead center, the angle of the crown combined with that of the head deck to form a wedge shaped combustion chamber with a pronounced Quench area. The spark plug protruded vertically into this chamber, which tended to cause a rapidly moving flame front during combustion.

The theory behind this sort of arrangement is that maximum BMEP is developed at relatively low engine speeds, resulting in an engine with a broad Torque curve. With its relatively flat torque characteristics, the "W" engine was well-suited to propelling both trucks and the heavier cars that were in vogue in the USA at the time of the engine's development.

The "W" had a dry weight of approximately 665 pounds (302 kg), depending on intake manifold and carburetion, and was a physically massive engine compared to its small block predecessor.

348

Versions FirstYear LastYear Model Name Features Power
1958 1961 Turbo-Thrust 4 barrel 250 hp (190 kW)
1958 1961 Super Turbo-Thrust "Tri-Power" 3x2 barrel 280 hp (210 kW)
1958 1961 Special Turbo-Thrust 4 barrel 305 hp (227 kW)
1958 1960 Special Super Turbo-Thrust "Tri-Power" 3x2 barrel 315 hp (235 kW)
1959 1960 Special Turbo-Thrust 4 barrel 320 hp (240 kW)
1959 1961 Special Super Turbo-Thrust "Tri-Power" 3x2 barrel 335 hp (250 kW)
1960 1961 Special Turbo-Thrust 4 barrel 340 hp (250 kW)
1960 1961 Special Super Turbo-Thrust "Tri-Power" 3x2 barrel 350 hp (260 kW)

The first iteration of the "W" engine was the 1958 "Turbo-Thrust" 348-cubic-inch (5.7 L) originally intended for use in Chevrolet trucks, but also introduced in the larger, heavier 1958 passenger car line. Bore was 4.125 in (104.8 mm) and stroke was 3.25 in (82.5 mm), resulting in a substantially Oversquare design. This engine was superseded by the 409 as Chevrolet's top performing engine in 1961 and went out of production for cars at the end of that year. It was produced through 1964 for use in large Chevrolet trucks.

With a four-barrel Carburetor, the base Turbo-Thrust produced 250 hp (186 kW). A special "Tri-Power" triple-two-barrel version, called the "Super Turbo-Thrust" produced 280 hp (209 kW). A "Special Turbo-Thrust" upped the output to 305 hp (227 kW) with a single large four-barrel. Mechanical lifters and the three two-barrel carburetors brought the "Special Super Turbo-Thrust" up to 315 hp (235 kW). For 1959 and 1960, high-output versions of the top two engines were produced with 320 hp (239 kW) and 335 hp (250 kW) respectively. In 1961, power was again increased to 340 hp (253 kW) for the single four-barrel model, and 350 hp (261 kW) when equipped with three two-barrels.

409

A 409-cubic-inch (6.7 L) version was Chevrolet's top regular production engine from 1961 to 1965, with a choice of single- or dual-four-barrel carburetors. Bore and stroke were both up from the 348 at 4.312 in (109.5 mm) by 3.50 in (88.9 mm). On December 17, 1960, the 409 engine was announced along with the Impala SS (Super Sport) model. The initial version of the engine produced 360 hp (268 kW), with a single-four-barrel Carter AFB carburetor. The same engine was upped to 380 hp (283 kW) in 1962. A 409 horsepower (305 kW) version of this engine was also available, developing 1 hp per cubic inch with a dual-four-barrel aluminum intake manifold and two Carter AFB carburetors. In the 1963 model year, output reached 425 hp (317 kW) at 6200 rpm with the 2X4 setup, 11.25:1 compression and a solid lifter camshaft. This engine was immortalized in the Beach Boys song titled "409 (song)". The engine was available through mid 1965 when it was replaced by the 396-cubic-inch 425 hp (317 kW) Mark IV big-block engine. In addition, a 340 hp (253 kW) version of the 409 engine was available from 1963–1965, with a single-four-barrel cast-iron intake mounting a Rochester 4GC carburetor, and a hydraulic-lifter camshaft.

427 (Z11)

A special 427 cubic inches (7.00 L) version of the 409 engine was used in the 1963 Chevrolet Impala Sport Coupe ordered under Chevrolet Regular Production Option Z11. This was a special package created for drag racers, including aluminum engine and body parts and a cowl-induction air intake system, along with the 427 engine. The aluminum body parts were fabricated in Flint, MI at the facility now known as GM Flint Metal Center[1]. Unlike the later second generation 427, it was based on the W-series 409 engine, but with a longer 3.65 in (92.7 mm) stroke. A high-rise two piece aluminum intake manifold and dual Carter AFB carbs fed a 13.5:1 compression ratio to produce an under-rated 430 hp (321 kW) and 435 ft·lbf (590 N·m). 50 RPO Z11 cars were produced at the Flint plant. GM Documents exist that show 50 Z11 engines were built at the GM Tonawanda engine plant for auto production, and 20 partial engines were made for replacement/over the counter use. No evidence from GM has been found that show 57 cars were built.

Generation 2: Mark IV Series

Development of the second generation big-block started with the so-called Mystery Motor used in Chevrolet's 1963 Daytona 500 record-setting stock cars. This "secret" engine was a substantially modified form of the "W" engine, and was subsequently released for production use in mid-1965 as the Mark IV, referred to in sales literature as the "Turbo-Jet V8."

Where the Mark IV differed from the "W" engine was in the placement of the valves and the shape of the combustion chambers. Gone was the chamber-in-block design of the "W" (which caused the power curve to drastically sag above 6500 RPM), and in its place was a more conventional wedge chamber in the cylinder head, which was now attached to a conventional 90 degree deck. The valves continued to use the displaced arrangement of the "W" engine, but were also inclined so that they would open away from the combustion chamber and cylinder walls, a design feature made possible by Chevrolet's stud mounted rocker arms. This alteration in valve placement resulted in a significant improvement in Volumetric efficiency at high RPM and a substantial increase in power output at racing speeds. Owing to the appearance of the compound angularity of the valves, the automotive press dubbed the engine the "porcupine" design.

As part of the head redesign, the spark plugs were relocated so that they entered the combustion chamber at an angle relative the cylinder Centerline, rather than the straight in relationship of the "W" engine. This too helped high RPM performance. Due to the new spark plug angle, the clearance provided by the distinctive scalloped valve covers of the "W" model was no longer needed, and wide, rectangular covers were used.

In all forms (except the ZL-1 Can-Am model) the "rat motor", as it was later nicknamed (the small-block engine being a "mouse motor"), was slightly heavier than the "W" model, with a dry weight of about 685 pounds (310.7 kg). Aside from the new cylinder head design and the reversion to a conventional 90 degree cylinder head deck angle, the Mark IV shared many dimensional and mechanical design similarities with the "W" engine. The cylinder block, although more substantial in all respects, used the same cylinder bore centers and main bearing dimensions as the older engine (in fact, the shorter stroke 348 and 409 crankshafts could be installed without modification). Like its predecessor, the Mark IV used crowned pistons, which were Casting for conventional models and Impact extruded (Forge), Solid skirt types in high performance applications.

Also retained from the "W" design were the race-proven Moraine M400 aluminum bearings first used in the 409, as well as the highly efficient "side oiling" lubrication system, which assured maximum oil flow to the main and connecting rod bearings at all times. These features, along with the robust crankcase design, sturdy forged steel crankshaft and massive four bolt main bearing caps used in the high performance versions, resulted in what many have considered to be the most rugged and reliable large displacement automotive V8 engine design of all time.

396 and 402

The 396-cubic-inch (6.5 L) V8 was introduced in the 1965 Corvette as the L78 option and in the Z16 Chevelle. It had a bore of 4.094 in and stroke of 3.76 in (104 mm by 96 mm), and produced 425 hp (317 kW) and 415 ft·lbf (563 N·m). This version of the 396 was equipped with four bolt main bearing caps and was very comfortable with being operated in the upper 6000 rpm range.

Introduced in 1970, the 402-cubic-inch (6.6 L) was a 396-cubic-inch bored out by 0.030 in (0.8 mm). Despite the fact that it was 6 cubic inches (98 cc) larger, Chevy continued marketing it under the popular "396" label in the smaller models, and as the "Turbo-Jet 400" in the full-size series.

Power rating(s) by year:

  • 1965: 375 hp (280 kW)
  • 1966: 325 hp (242 kW)/350 hp (260 kW)/360 hp (270 kW)/375 hp (280 kW)
  • 1967: 325 hp (242 kW)/350 hp (260 kW)/375 hp (280 kW)
  • 1968: 325 hp (242 kW)/350 hp (260 kW)/375 hp (280 kW)
  • 1969: 265 hp (198 kW)(2bbl)/325 hp (242 kW)/350 hp (260 kW)/375 hp (280 kW)
  • 1970: 330 hp (250 kW)/350 hp (260 kW)/375 hp (280 kW)
  • 1971: 300 hp (220 kW)
  • 1972: 240 hp (180 kW)

Used in:

427

L36 427 in a 1966 Chevrolet Corvette
L71 427 in a 1967 Chevrolet Corvette

The highly successful and versatile 427 cubic inch (7.0 L) version of the Mark IV engine was introduced in 1966 as a production engine option for full sized Chevrolets and Corvettes. The bore was increased to 4.25 inches (108 mm), with power ratings varying widely depending on the application. There were smooth running versions with Hydraulic lifters suitable for powering the family Station wagon, as well as rough idling, high-revving solid lifter models that resembled racing powerplants.

Not every version of the 427 was available in every car, and ordering the highest performance versions often required that other options be added to or deleted from the car (for example, power steering wasn't available with the high performance models). This relationship between engine configuration and vehicle options often resulted in what was jokingly referred to as a "racing Taxicab," the description usually applied to a minimally equipped, plain looking, two door Biscayne Sedan (car) fitted with the 425 horsepower (317 kW) version of the 427— (RPO L72), resulting in a vehicle whose performance was the polar opposite of a taxi. This lightweight, big-block Biscayne was also commonly referred to as "Bisquick."

Perhaps the ultimate 427 for street applications was the 435 horsepower (324 kW) L71 version available in 1967 to 1969 Corvettes, and in the Italian Iso Grifo. This engine was identical to the 425 hp (317 kW) L72 427 (first introduced in 1966) but was fitted with three two barrel carburetors in lieu of the L72's single 4 barrel. Both engines utilized the same high lift, long duration, high overlap camshaft and large port, cast iron heads in order to maximum cylinder head flow (and, hence, engine power) at elevated engine operating speeds. Consequently, the engines offered very similar performance and resulted in a car whose performance was described by one automotive journalist as "the ultimate in sheer neck-snapping overkill." Typical magazine road tests of the day yielded sub-6 second zero to 60 miles per hour (97 km/h) times and quarter miles in the mid 13 second/106 MPH range for both the L72 and L71.

RPO L89 was an L71 fitted with aluminum heads (often dealer installed). While this option produced no power advantage, it did reduce engine (and hence, vehicle) weight by roughly 75 pounds (34 kg). This resulted in superior vehicle weight distribution for improved handling, although any difference in straight line performance was essentially negligible.

The most legendary version of the 427 was undoubtedly the 1969 ZL1 engine. It was developed primarily for Can-Am racing, where it was very successful in cars like the Chaparrel 2F and McLaren M8B. The ZL1 had specifications nearly identical to the production L88 version of the 427, but featured an all-aluminum cylinder block in addition to aluminum cylinder heads, which dropped total engine weight into small block Chevy territory (approx. 575 lb/261 kg dressed). The engine was also fitted with the new open combustion chamber cylinder heads, a light weight aluminum water pump, a camshaft that was slightly "hotter" than the L88's and a specially tuned aluminum intake manifold. Like the L88, the ZL1 required 103 octane RON (minimum) fuel, which made both engines largely unsuitable for street use in an era where 102 octane RON (Sunoco 260) represented the highest octane gasoline sold at common retail stations. Impressive as the ZL1 was in its day and despite the "larger than life legends" surrounding it, actual engine dyno tests of a certified production line stock ZL1 revealed 376 SAE net HP, with output swelling to 524 Gross HP with the help of optimal carb. and ignition tuning, open long tube racing headers and with no power sapping engine accessories or air cleaner in place. ZL1 DYNO TEST - COPO CAMARO WEBSITE A second engine dyno test conducted on a second production line stock (but recently rebuilt and partially blueprinted) ZL1 revealed nearly identical figures for the various "Gross" conditions. 2nd ZL1 DYNO TEST Magazine tests of the ZL1 were quite rare due to the rarity of the engine itself. "High Performance Cars" tested a production line stock version and recorded a 13.1 second/110 MPH quarter mile, which correlates quite well with the previously referenced 376 Net HP figure. "Super Stock and Drag Racing Magazine" recorded an 11.62 second/122.15 MPH quarter mile in a ZL1 Camaro that was professionally tuned and driven by drag racing legend Dick Harrell, although that car was equipped with open long tube S&S equal length headers, drag slicks and minor suspension modifications. The 122.15 MPH trap speed indicated very low 11 second ET potential (e.g. with larger drag slicks) and suggested something on the order of 495 "as installed" HP in that modified configuration. This large difference in power suggests that the OEM exhaust manifolds and exhaust system were very restrictive in the ZL1 application, as was also the case with the similar L88.

The race-prepped ZL1s that were utilized in Can-Am racing were capable of developing something on the order of 600 "as raced" HP as the result of complete engine blueprinting, fuel injection, more aggressive cam-shaft grinds, custom fabricated, power optimizing long tube racing headers, dry sump lubrication and various other power and durability enhancing changes. It is this figure that is often erroneously cited as the "actual" output of production line stock ZL1 passenger car engines (e.g. 1969 COPO 9560 Camaro).

The 4718 USD cost of the ZL1 option doubled the price of the 1969 Corvette, but resulted in a car with exceptional performance for its day. Just two production Corvettes (factory option at dealer) and 69 Camaros (non-dealer option from factory - COPO 9560) were built with the ZL1.

Chevrolet capitalized on the versatility of the 427 design by producing a wide variety of high performance, "over the counter" engine components (marketed as "heavy duty" or "extra capacity" components to mask their intended racing application), as well as ready-to-race "replacement" engines in shipping crates. Some of the components were developed to enhance the engine's reliability during high RPM operation, possibly justifying the use of the description "heavy duty." However, most of these items were racing parts originally designed for Can-Am competition that found their way on to dealers' shelves, and were meant to boost the engine's already impressive power output. As a result of this activity, the 427 quickly became dominant in Drag racing.

Beginning in 1969, the highest performance 427 models were fitted with the new open (vs. closed) chamber cylinder head, s which along with design improvements in crankshafts, connecting rods and pistons adopted from the Can-Am development program, resulted in an engine with substantially increased performance and reliability. This development culminated in a specialty version of the engine called the ZLX, which was essentially a ZL1 engine built with the L88 engine's sturdy, four bolt main bearing iron block (it has been suggested that "ZLX" was a code name for ZL1 crossover). The ZLX, available as a short block assembly or complete "replacement" engine in the crate from a few dealers, was a resounding success and became a best-seller by Aftermarket (automotive) standards—the closest thing to an all-out competition engine ever offered to the general public.

Chevrolet gave all 427 engines except the ZL1 a torque rating of 460 ft·lbf (624 N·m).

FirstYear LastYear EngineCode Features Compressionratio FactoryGross Power

Rating

1966 1969 L36 4-barrel 10.25:1 390 hp (291 kW)
1966 1966 L72 4-barrel + solid-lifters, more aggressive cam and high flow cylinder heads 11.00:1 425 hp (317 kW)[1]
1967 1969 L68 L36 with 3x2-barrel carbs. 10.25:1 400 hp (298 kW)
1967 1969 L71 L72 with 3X2 barrel carbs. 11.00:1 435 hp (324 kW)
1967 1969 L89 L71 + aluminum heads; RPO L89 also applied to L78 "375 HP" 396 engine with aluminum head option. 11.00:1 435 hp (324 kW)
1967 1969 L88 Racing-spec cam, high-flow aluminum heads (casting #s varied by model year) and some upgraded, competition-grade parts 12.50:1[2] 430 hp (321 kW)[3]
1969 1969 ZL1 Aluminum block with open chamber "3946074" aluminum heads; cam even "hotter" than L88's; upgraded parts similar to L88's 12.00:1 430 hp (321 kW)
1970 1977(?) ZLX L88-ZL1 hybrid; iron block with aluminum heads 12.25:1 430(?) hp (321 kW)
Notes:
  1. ↑ Chevrolet actually advertised this engine as 450 hp (336 kW) for a short period of time. There is speculation over whether this engine actually put out 450 Gross HP, or if this was a marketing oversight that was later corrected.
  2. ↑ L88 had a 12.5:1 compression ratio with closed chamber heads except during the last half of 1969, when it had open chambered heads that yielded 12.0:1
  3. ↑ L88 was rated for 430 hp (320 kW) at 5200 rpm. With stock exhaust manifolds and operation in the 6,800 rpm range, it was generally accepted that the engine was capable of producing in excess of 500 Gross HP with free-flowing (open) long tube headers.

454

The big-block was expanded again for 1970 to 454 cubic inches (7.4 L) with a 4.251 in (108 mm) bore and 4 in (102 mm) stroke. The 1970 Chevy Corvette LS5 version of this engine produced 390 hp (291 kW) and 500 ft·lbf (678 N·m), and the LS6 engine was rated at 450 hp (336 kW). It has been suggested that the LS6 was substantially underrated and actually produced well over 500 horsepower (370 kW) as delivered from the factory, although there is no empirical evidence to support this claim. Indeed, the AHRA ASA Class record holding Chevelle LS6 for the 1970 season posted a record setting trap speed of 106.76 mph (171.81 km/h) "1970 ASA LS6 454 Records", which suggests something on the order of 370 "as installed" (SAE Net) HP for a 3,900 pounds (1,800 kg) car and driver combination.

A 465 hp (347 kW) and 490 lb·ft (664 N·m) version of the 454, dubbed LS7 was also designed but never went to production. However, a handful of LS7 intake manifolds were produced and sold by a handful of Chevy dealers as performance parts. The LS7 was later offered as a crate engine from GM and advertised at 500 hp (370 kW).

Power began falling off after 1970, with the 1971 LS5 producing 365 hp (272 kW) and 465 lb·ft (630 N·m), and the LS6 option coming in at 425 hp (317 kW) and 475 lb·ft (644 N·m). Only the LS5 remained in 1972, when SAE net power ratings and the move towards emission compliance resulted in to 270 hp (201 kW) and 390 lb·ft (529 N·m). The 1973 LS4 produced 275 hp (205 kW) and 390 lb·ft (529 N·m), with 5 hp (4 kW) and 10 lb·ft (14 N·m) gone the following year. Hardened valve seats helped allow these engines to last much longer than the earlier versions, even without the protection previously provided by lead from fuel. 1974 was the last year of the 454 in the Corvette though the Chevelle offered it in the first 1/2 of the 1975 model year. It was also available in the full size Impala/Caprice until model year 1976.

GM continued to use the 7.4 L (454 cu in) in their truck line, introducing a new Vortec 7400 version in 1996. GM also introduced the 7.4 L 454 EFI in 1990 (known as the GEN V; the previous generation was known as the Mark IV produced between 1965-90; the GEN prefix was used since Ford Motor Company owns the Mark V naming rights since it was used on a Lincoln (automobile) automobile between 1977-79), which was electronically fuel injected giving more power and torque. Instead of the regular 290 hp (220 kW), the 454 EFI version cranked out 365 hp (272 kW) and 415 lb·ft (563 N·m) of torque. The 454 EFI power ratings were very similar to the early 1970s LS5 454, which was found in early 1970s corvettes and chevelles. The 7.4 L 454 EFI was found on GM 3500 trucks throughout the early 1990s until replaced with the Vortec 7400 (GEN VI) in 1996.

  • 1970–1976 Chevrolet Cars
  • 1970–1974 Chevrolet Corvette

502

The Chevy 502 V8The 502-cubic-inch (8.2 L) was offered in various fleet and service vehicles in the late 80's and early 90's . It had a bore of 4.466 with a stroke of 4.00 and was a Cast iron 4-bolt main block. Later GM offered it in their Performance Parts catalog, available as multiple Crate motor with horse power ratings between 338 hp (252 kW) to 502 hp (374 kW), and torque of 470 lb·ft (637 N·m) to 567 lb·ft (769 N·m) in "Base" and "Deluxe" packages.[1] The "Ram Jet 502"[2] (502 hp (374 kW) / 565 lb·ft (766 N·m)) crate motor was offered with Fuel injection, and came as a Turn key setup which includes all the wiring and electronics needed to operate in any vehicle.

572

Chevrolet began offering an 572-cubic-inch (9.4 L) "crate motor" in 2003 which produced 720 hp (537 kW) and 685 lb·ft (929 N·m) of torque,[3] and more recently a 620 hp (462 kW) / 650 lb·ft (881 N·m) version capable of running on 93 octane street gasoline.[4]

The aftermarket

The large variety of aftermarket components manufactured for the big block family makes it possible to build a complete big block engine that contains no Chevrolet components. Blocks made of both iron and aluminum alloys are available in stock configurations and also with increased deck height to allow longer stroke or more favorable rod length ratios, providing the ability to make 632-cubic-inch (10.4 L) engines, and larger.

Commercial applications

Mark IV engines saw extensive application in Chevrolet and GMC medium duty trucks, as well as in Blue Bird Corporation All American and TC/2000 transit buses (the latter up until 1995, using a purpose-built, carbureted 427). In addition to the 427, a 366-Cubic inch (6.0 Liter) version was produced for the commercial market. Both the 366 and 427 commercial versions were built with a raised deck, four bolt main bearing cap cylinder block to accommodate an extra oil control ring on the pistons. Unfortunately, the raised deck design complicated the use of the block in racing applications, as standard intake manifolds required spacers for proper fit. Distributors with adjustable collars that allowed adjustments to the length of the distributor shaft also had to be used with 366 and 427 truck blocks.

Mark IV engines also found themselves widely used in power boats, a natural application for these robust power plants. Many of these engines were ordinary Chevrolet production models that were fitted with the necessary accessories and drive system to adapt them to marine propulsion. Mercury Marine, in particular, was a major user of the Mark IV in marine drives, and relabeled the engines with their corporate logo.

8100

The Vortec 8100 7th generation (known as gen VII) Chevrolet big block, has the same bore as a 454 (4.25 inches), but has a stroke of 4.37 inches (111 mm). It is similar to the smaller GM LS engine family in that it has coil-on-plug ignition and a 1-8-7-2-6-5-4-3 firing order. It was used in 3/4 ton and larger light trucks, and medium duty commercial vehicles. http://en.wikipedia.org/wiki/GM_Vortec_engine#8100 Produced in the years of 2001–2006.5.

See also

From the 1950s through the 1970s, each GM division had its own V8 engine family. Many were shared among other divisions, but each design is most-closely associated with its own division:

GM later standardized on the later generations of the Chevrolet design:

Notes

References

  • Peter C Sessler (1999). Ultimate American V8 Engine Data Book. MotorBooks/MBI Publishing Company. ISBN 0-7603-0489-0. 

www.chevy-wiki.com

Chevrolet Small-Block engine

Chevrolet Small-Block V8 engine 265 283 307 327 302 400 262 305 350
Manufacturer: General Motors Corporation
Production: 1955–2002
Successors: GM LT engine, GM LS engine
Type: Small-block V8
Production: 1954–1957
Displacement: 265 cu in (4.3 L)
Power: 162 hp (121 kW)-240 hp (179 kW)
Bore and Stroke: 3.750 in × 3.00 in (95.2 mm × 76.2 mm)
Production: 1957–1967
Displacement: 283 cu in (4.6 L)
Power: 220 hp (164 kW)-315 hp (235 kW)
Bore and Stroke: 3.875 in × 3.00 in (98.4 mm × 76.2 mm)
Production: 1968–1973
Displacement: 307 cu in (5 L)
Power: 115 hp (86 kW)-200 hp (149 kW)
Bore and Stroke: 3.875 in × 3.25 in (98.4 mm × 82.5 mm)
Production: 1962–1969
Displacement: 327 cu in (5.4 L)
Power: 250 hp (186 kW)-375 hp (280 kW)
Bore and Stroke: 4.000 in × 3.25 in (101.6 mm × 82.5 mm)
Production: 1967–1969
Displacement: 302 cu in (4.9 L)
Power: 290 hp (216 kW)
Bore and Stroke: 4.000 in × 3.00 in (101.6 mm × 76.2 mm)
Production: 1970–1981
Displacement: 400 cu in (6.6 L)
Power: 150 hp (112 kW)-265 hp (198 kW)
Bore and Stroke: 4.125 in × 3.75 in (104.8 mm × 95.2 mm)
Production: 1975–1976
Displacement: 262 cu in (4.3 L)
Power: 110 hp (82 kW)
Bore and Stroke: 3.670 in × 3.10 in (93.2 mm × 78.7 mm)
Production: 1976–1992
Displacement: 305 cu in (5 L)
Power: 130 hp (97 kW)-250 hp (186 kW)
Bore and Stroke: 3.736 in × 3.48 in (94.9 mm × 88.4 mm)
Production: 1967–2002 (production ceased in 2002 for USA production only; still manufactured in Mexico for GM's Goodwrench Replacement Engines)
Displacement: 350 cu in (5.7 L)
Power: 145 hp (108 kW)-370 hp (276 kW)
Bore and Stroke: 4.000 in × 3.48 in (101.6 mm × 88.4 mm)

Chevrolet's Small-block V8 is a famous Automobile engine. Soon after being introduced, it quickly gained popularity among Stock car racers, becoming known as the "Mighty Mouse" motor, after the popular cartoon character of the time. This was often shortened to the "mouse motor"[1] for its compact dimensions and lighter weight, compared to other V8 engines of the time (Chevrolet would later introduce the larger big block engine, which gained the nickname "Rat motor"). Production of the small-block began in 1955 with the 265 ci. engine. By 1957 it had grown to 283 cu in (4.6 L), and with the optional Rochester mechanical fuel injection, it became one of the first production engines ever to make one horsepower per cubic inch. This engine was used to power the Corvette, and the Bel Air at that time. It would later be extended to other vehicles as well, and replace the old style 265 V8s. The displacement changed over the years, eventually reaching 400 cu in (6.6 L), but none caught on like the 350 cu in (5.7 L) small-block. This engine is still in production today at General Motors Toluca, Mexico plant (primarily for the GM over-the-counter Goodwrench powerplants), but is no longer offered in current model year vehicles since the year 2004. Its production numbers were impressive, with more than 90,000,000 built. It has been produced in carbureted, mechanical fuel injection, and electronic fuel injection forms.

From 1955-74, the small-block engine was known as the "Turbo-Fire V8".

Although Buick, Cadillac (automobile), Oldsmobile, and Pontiac also designed V8 engines (see list of GM engines), it was Chevrolet's 350 cu in (5.7 L) small-block that became the GM corporate standard. Over the years, every American General Motors division except Saturn Corporation used the Chevrolet small-block, and its descendants (see GM LT engine and GM LS engine) continue as the company's mainstream V8 design today.

The small-block was on the Ward's 10 Best Engines list.

Chevrolet tested the small-block twice with no water and no oil at wide-open throttle. The first time it lasted an hour and 15 minutes and the second time it lasted two hours.[2]

Major Versions

The original design of the small block remained remarkably unchanged for its production run, which began in 1955 and ended, in passenger vehicles, in 2003. The engine is still being built today for many aftermarket applications, both to replace worn-out older engines and also by many builders as high-performance applications. There were, however many minor changes made to the engine over the years; these changes are listed below.

  • 1955 - The first year of introduction in 265 cu in (4.3 L) only. As was fairly common for the time, no provision for an oil filter was included in the engine design.
  • 1956 - Oil filtration was introduced, using a sock style filter in a canister.
  • 1957 - The engine came with only front mounts, the side mount bosses were present but not drilled and tapped leaving its retrofitting problematic.
  • 1962 - The block's cylinder wall casting was revised to allow four inch bores. Previously, only certain years of the 283 engine (1958-1962) could be bored safely to four inches.
  • 1968 - The main journal diameter was increased to 2.45 in from 2.30 in and the connecting rod journal diameter was increased to 2.10 in from 2.00 in. This allowed the use of cast iron crankshafts as the previous parts were made of forged steel. The rod bolts were changed from 11/32 in. diameter to 3/8 inch. Additionally, the canister/sock style oil filter was now converted to use spin on filters. The oil fill location was moved from a tube on the front of the intake manifold to a cap on either side valve cover.
  • 1986 - The rear main seal was changed from a 2-piece rubber design to a 1-piece rubber design that used a mounting appliance to hold it in place. This necessitated a change in the flywheel/flexplate bolt pattern as well.
  • 1987 - The valve cover surfaces were changed such that cylinder head mounting lip was raised and the bolt location was moved from 4 bolts on the perimeter, to 4 bolts down the centerline of the valve cover (this design debuted on the Corvette in 1985, and Chevrolet 4.3 L the year before). Also changed were the mounting angles of the center 2 bolts on each side of the intake manifold (from 90 degrees to 73 degrees) and the lifter bosses were increased in height to accept roller lifters. The alloy heads for use in the Corvette still retain the non-angled bolts (center 2 bolts attaching to the intake). Also all carburetors were done away with and replaced by TBI (throttle-body injection) fuel injection that acts some what like a carburetor.
  • 1996 - This was the last change for the Generation I engine, and continued through the end of the production run in 2003; all 1997-2003 Generation I engines were Vortec truck engines. The cylinder heads were redesigned using improved ports and combustion chambers similar to those in the Generation II LT1. Again, the intake manifold bolt pattern changed - four bolts per cylinder head are used instead of the traditional six. This change resulted in significant power increases.
SB2 and SB2.2

(Small Block/second generation) This engine was produced from 1996 to the present for racing applications only. The cylinder heads were redesigned and the lifter bores were offset. The valve sequence for each head was changed from the traditional E-I-I-E-E-I-I-E to a new I-E-I-E-E-I-E-I and because of this the camshaft was redesigned.

Generation II

LT1 from a 1993 Chevrolet Camaro Z28

See the GM LT engine page for more information on the Generation II small-block V8s, which differ mainly in their reverse-flow cooling system.

Generation III / IV

LS1 from a 1998 Chevrolet Camaro Z28

See the GM LS engine page for more information on the current family of General Motors small-block V8s.

Early Small Blocks

The first small block Chevrolet V-8 was a 265 cu in (4.3 L) engine that was developed in 1955 for the Corvette. The small block has remained popular due to its relatively compact size, light weight, and extensive aftermarket support.

265

The 265 cu in (4.3 L) V8 was the first Chevrolet small block. Designed by Ed Cole's group at Chevrolet, it filled the power gap in the 1955 Corvette lineup, producing an impressive 250 hp (186 kW). The little engine went from drawings to production in just 15 weeks. Besides its compact dimensions, the small-block was known for its novel green-sand foundry construction process.

Dimensions were Oversquare - 3.75 in (95 mm) bore and 3 in (76 mm) stroke. The small-block's 4.4 in (111.8 mm) bore spacing would continue in use for decades. It was a Pushrod cast-iron engine with hydraulic Lifter and a 2-barrel or 4-barrel Rochester Carburetor. The 1955 conventional passenger car version produced 162 hp (121 kW) with a 2-barrel carburetor, or could be upgraded at extra cost to a "Power Pack" version conservatively rated at 180 hp (134 kW) with a four-barrel Rochester and dual exhaust. The first production year of this engine had no provision for oil filtration built into the block; however, an add-on filter mounted on the thermostat housing was installed during production. Due to the lack of adequate oil filtration provisions, the '55 model year block is typically only desirable to period collectors.

The 1956 Corvette introduced three versions of this engine - 210 hp (157 kW), 225 hp (168 kW) with twin 4-barrel carbs, and 240 hp (179 kW) with a high-lift cam.

  • 1955, 1956 Chevrolet Corvette
  • 1955 Chevrolet, 165 hp (123 kW) (2-barrel) and 195 hp (145 kW) (4-barrel)

283

The 283 cu in (4.6 L) V8 was introduced in 1957. It was a version of the 265 cu in (4.3 L) with a larger bore at 3.87 in (98 mm). There were five different versions ranging from 185 hp (138 kW) to 283 hp (211 kW) depending on whether a single carb, twin carbs, or fuel injection was used. Power was up a bit each year for 1958, 1959, and 1960.

The 1957 engine featured Ramjet mechanical Fuel injection, allowing the engine to produce 1 hp (1 kW) per cubic inch, an impressive feat at the time. For 1961, an amazing 315 hp (235 kW) was available from this unit.

  • 1957-1962 Chevrolet Corvette

302

Chevrolet produced a special 302 cu in (4.9 L) engine for Trans-Am Series racing from 1967-1969. It was the product of placing the 3-inch stroke crankshaft into a 4-inch bore block. Although the 283 also used a 3-inch stroke crankshaft, it was a low performance cast iron crankshaft. The crankshaft for the 302 was specially built of forged steel. This engine was used only in the first-generation Camaro Z28. Conservatively rated at 290 hp (216 kW), actual output was around 375 hp (280 kW). This block is one of 3 displacements that underwent a transformation for the 1968/1969 period when the main bearing size was increased from 2.30 in to 2.45 in.

307

A 307 cu in (5 L) version was produced from 1968 through 1973. Engine bore was 3.875 inches (98.4 mm) with a 3.25-inch (82.6 mm) stroke.

The 307 replaced the 283 in Chevrolet cars and produced 200 hp (149 kW) SAE gross at 4600 rpm and 300 lb·ft (407 N·m) of torque at 2400 rpm in the 1960s. The later emissions-modified versions produced just 115 hp (86 kW) SAE net, giving the engine one of the lowest power-per-displacement ratings of all time. Chevrolet never produced a high-performance version of this engine, though they did produce, for Outboard Marine Corporation, a high-performance marinized 307, rated at 235 hp (175 kW) and 245 hp (183 kW) SAE gross, depending on year, that shipped with the Corvette/Z-28's cast aluminum valve covers and Rochester QuadraJet carb. Chevy also built other versions of the OMC 307 rated at 210 hp (157 kW), 215 hp (160 kW) and 225 hp (168 kW) SAE gross.

One of the biggest myths about the 307 is that all the blocks were cast with a very low nickel content. However, some 307 blocks, such as casting number 3970020 with suffix VxxxxTHA (x's in place for date), had 010 and 020 stamped under the timing chain cover indicating high tin and nickel content.

327

The 327 cu in (5.4 L) V8, introduced in 1962, had a bore and stroke of 4 in (102 mm) by 3.25 in. Power ranged from 250 hp (186 kW) to 375 hp (280 kW) depending on the choice of carburetor or fuel injection, camshaft, cylinder heads, pistons and intake manifold. In 1962, the Duntov solid lifter cam versions produced 340 hp (254 kW), 344 lb·ft (466 N·m) with single Carter 4-brl, and 360 hp (268 kW), 352 lb·ft (477 N·m) with Rochester mechanical fuel injection. In 1964, horsepower increased to 365 hp (272 kW) for the now dubbed L76 version, and 375 hp (280 kW) for the fuel injected L84 respectively, making the L84 the most powerful naturally aspirated, single-cam, production small block V8 until the appearance of the 385 hp (287 kW), 385 lb·ft (522 N·m) Generation III LS6 in 2001. * L79, L84 1963-1965; Chevrolet Corvette. This block is one of three displacements that under went a major change in 1968/1969 when the main bearing size was increased from 2.30 to 2.4 inches (58.4–61.0 mm). In 1965 the SS malibu choice of the 327/350 hp know as the "L79", with a aluminum manifold, holley squarebore carb, chrome valve covers, a huge 8" balancer, huge 2.02" intake valves and could only be ordered with a 4 speed trans. It was also used in the Opel Admiral, Opel Diplomat and Opel Kapitan models.

400

A 400 cu in (6.6 L) small-block was introduced in 1970 and produced for 10 years. It had a 4.125-inch (104.8 mm) bore and a 3.75-inch (95.3 mm) stroke. Initial output was 265 hp (198 kW) and was only available equipped with a 2-barrel carburetor. In 1974 a 4-barrel version of the 400 was introduced,while the 2-barrel version stopped production in 1975. 1976 was the last year that the 400 was used in a Chevrolet Passenger car, available in both the A-Body and B-Body line. While popular with circle-track racers, the engine was prone to cooling troubles if cylinder heads without steam holes were used. They mostly put out 250 hp stock. Due to the way the block was designed, the 2 bolt main engines were stronger than the 4 bolt versions. The 509 2 bolt main block is the most desirable 400 block.

Later Small Blocks

This section documents the odd-size small blocks developed after the 350 appeared in 1969. Many of these basic blocks are variations of the 350 design.

262

The 262 was a 262 cu in (4.3 L) 90° Pushrod V8 with an iron block and heads. Bore and stroke were 3.67 in (93 mm) by 3.10 in (78.7 mm). Power output for 1975 was 110 hp (82 kW) and 195 lb·ft (264 N·m). The 262 was underpowered and was replaced by the 305 the following year.

This was Chevrolet's second 4.3 L-displacement powerplant; two other Chevrolet engines displaced 4.3 L: the Vortec 4300 (a V6 based on the Chevrolet 350, with two cylinders removed), and a derivative of the LT1 known as the L99 (using the 305's 3.736-inch bore, 5.94-inch connecting rods, and a 3-inch crankshaft stroke).

This engine was used in the following cars:

  • 1975-1976 Chevrolet Monza
  • 1975 Chevrolet Nova

267

The 267 was introduced in 1979 for GM F-Body(Camaro), G-bodies (Chevrolet Monte Carlo, El Camino, and Malibu Classic) and also used on GM B-body cars (Impala and Caprice models). The 267 cu in (4.4 L) had the 350's crankshaft stroke of 3.48" and the smallest bore of any small-block, 3.500 in. The 3.500" bore was also used on the 200 cu in (3.3 L) V6, which was introduced a year earlier. (The 200 was a Chevrolet V6 engine based on the small block with the #3 and #6 cylinders removed).

It was available with a Rochester Dualjet 210 - effectively a Rochester Quadrajet with no rear barrels. After 1980, electronic feedback carburetion was used on the 267.

While similar in displacement to the other 4.3-4.4 L V8 engines produced by General Motors (including the Oldsmobile V8 engine and Pontiac V8 engine, the small bore 267 shared no parts with the other engines and was phased out after the 1982 model year due to inability to conform to emission standards. Chevrolet vehicles eventually used the 305 cu in (5 L) as its base V8 engine.

305

The 305 variant of the small-block Chevrolet had a displacement of 305 cu in (5 L) with a 3.736-inch (95 mm) bore and 3.48-inch (88.4 mm) stroke. The 262 was considered underpowered for use in vehicles with a wheelbase greater than 110 inches, so GM engineers decided to increase the bore diameter from 3.671 to 3.736 inches (93.2–94.9 mm) and increase the stroke from 3.10 to 3.48 inches (78.7–88.4 mm) (from the 350). Some performance enthusiasts have noted a marked resistance to performance upgrades on the 305 because of its small bore, poor selection of aftermarket cylinder heads, and the relatively high availability of 350 cu in (5.7 L) engines.

Induction systems for the 305 included carburetors (both 2 and 4-barrel), throttle-body injection (TBI), tuned-port fuel injection (TPI), and sequential fuel injection (GM Vortec).

After 1996, its usage was limited to light trucks and SUVs as the Vortec 5000.

Year hp (kW) lb·ft (N·m)
1976 140 250 w/2bbl.
1977 145 245 w/2bbl.
1978 140 240 w/2bbl.
1978 160 235 w/4bbl.
1979 130 245 w/2bbl.
1979† 125 235 w/2bbl.
1980 155 240 w/4bbl.
1981 150 240 w/4bbl

† California Emissions

The 305 was used in the following cars:

LG3

Years:1976-1980

Dualjet 2 bbl carb version with 8.5:1 compression.

LG4

Years: 1980-1987

The LG4 was the "low output" 305 cu in (5 L) (compared to the L69). It produced 150 hp (112 kW)-170 hp (127 kW) and 240 lb·ft (325 N·m)-250 lb·ft (339 N·m). The addition of a knock sensor for the engine management system in 1985 allowed an increase in compression and a more aggressive spark timing map in the ECM. As a result power increased for the 1985 models to 165 hp (123 kW) from the 150 hp (112 kW) rating in 1984.

L69

Years: 1983-1986

The L69 was the last true H.O. engine. The High Output 5 L (305 cu in) , featuring higher compression of 9.5:1 with heads of the to-be-discontinued LU5 Cross-Fire Fuel injection engine, and utilizing camshaft and 4" catalytic converter of the 5.7 L (350 cu in) L83 which was used on the Corvette of 1982 and 1984. Complete with a 2.75 inch exhaust system, topped by a recalibrated 4-barrel carburetor, dual snorkel air cleaner assembly, aluminum intake manifold, aluminum flywheel, electric cooling fan, and furthermore a knock sensor including more aggressive spark timing, this engine produced 190 hp (142 kW) @ 4800 and 240 lb·ft (325 N·m) of torque @ 3200 rpm. In most cases, being mated to a 3.73 or 3:42 ratio limited slip rear axle and a T5 5-speed or 700R4 automatic, this engine provided its driver with a wide range of rpm to play in.

LE9

Years: 1981-1986

The LE9 5 L (305 cu in) was the truck/van version of the High Output 305. It also had flattop pistons for a 9.5:1 compression ratio, the "929" truck 350 camshaft for more torque, 14022601 casting heads featuring 1.84/1.50" valves and 58 cc chambers, a specially calibrated 4bbl Q-Jet, the hybrid centrifugal/vacuum advance distributor with ESC knock sensor setup, and lower restriction exhaust. The engine made 210 hp (157 kW) @ 4,600 and 250 lb·ft (339 N·m) @ 2,000 rpm.

L03

Years: 1987-95

The L03 was the "low output" 5 L (305 cu in) (compared to the 305 TPI LB9). It produced 170 hp (127 kW) and 255 lb·ft (346 N·m) of torque (190 hp (142 kW) at 4,400 rpm and 275 lb·ft (373 N·m) at 2,400 in 1993-1995 GM trucks). This engine used Electronic fuel injection. The TBI uses a unique injector firing scheme: for every rotation of the engine, each injector fired twice.

LB9

Years: 1985-1992

Introduced in 1985, the LB9 was the first Chevrolet small block to have tuned-port fuel injection (TPI). It was introduced with 215 hp (160 kW) and 275 lb·ft (373 N·m) and varied between 190 hp (142 kW)-230 hp (172 kW) (with 275 lb·ft (373 N·m)-300 lb·ft (407 N·m) of torque) over the years offered. It was an option on all 1985-1992 Chevrolet Camaro & Pontiac Firebird models.

350

Not to be confused with Buick V8 engine, Oldsmobile V8 engine, or Pontiac V8 engine.

The first generation of Chevrolet small-blocks began with the 1955 Chevrolet 265 cu in (4.3 L) V8. But it was the 350 cu in (5.7 L) series that came to be emblematic of the Chevrolet small block V8 engine. The engine's physical dimensions (Oversquare 4.00-inch bore and 3.48-inch stroke, 102 mm by 88 mm) are nearly identical to the 436 hp (325 kW) LS3 engine of today, but much has changed. It is by far the most widely used Chevrolet small-block; it has been installed in everything from station wagons to sports cars, in commercial vehicles, and even in boats and (in highly modified form) airplanes.

First usage of the 350 was in the 1967 Chevrolet Camaro and 1968 Nova producing 295 horsepower (gross); other Chevrolet vehicle lines followed suit in the year 1969.

The GM Goodwrench 350 crate engine comes in several variations. The lowest priced uses the pre-1986 four-bolt casting molds with two dipstick locations; pre-1980 on the driver's side and post-1980 on the passenger's side. This engine was produced in Mexico since 1981 as the Targetmaster 350, and now the GM Goodwrench 350.

ZQ3

Years: 1969, 1970, 1972-1975

The ZQ3 was the standard engine in the 1969-1970 Chevrolet Corvette. It was a 300 hp (224 kW) version of the 350 cu in (5.7 L) small-block, with 10.25:1 compression and hydraulic lifters. It used a Rochester "4MV" Quadra-Jet 4-barrel carburetor. This was the first block produced that featured the larger 2.45 inch main bearing versus the older 2.30 inch main bearing in 1968/1969.

The 1969 ZQ3 produced 200 hp (149 kW) and 300 lb·ft (407 N·m) with 8.5:1 compression, dropping another 10 hp (7 kW) in 1973. 1975 saw the ZQ3 at 165 hp (123 kW) and 255 lb·ft (346 N·m).

L46

Years: 1969, 1970

The L46 was an optional engine on the 1969-1970 Chevrolet Corvette. It was a 349 hp (260 kW), 380 lb·ft (515 N·m) version of the ZQ3 with higher 11:1 compression.

LT-1

LT-1 from a 1970 Chevrolet Camaro Z28

Years: 1970-1972

The LT-1 was the ultimate 350 cu in (5.7 L) V8, becoming available in 1970. It used solid lifters, 11:1 compression, a high-performance camshaft, and a Holley four-barrel carburetor on a special aluminum intake to produce 370 hp (276 kW) and 380 lb·ft (515 N·m). It was available on the Corvette and Camaro Z28. Power was down in 1971 to 330 hp (246 kW) and 360 lb·ft (488 N·m) with 9:1 compression, and again in 1972 (the last year of the LT-1, now rated using net, rather than gross, measurement) to 255 hp (190 kW) and 280 lb·ft (380 N·m).

There was also a later small-block engine called the "LT1".

L48

Years: 1967-1980

The L-48 is the original 350 cu in (5.7 L), available only in the Camaro or Chevy II/Nova in '67 & '68. In '69 it was used in almost everything; Camaros, Corvettes, Impalas, Chevelles & Novas. From '75-'80 it was available only in the Corvette. L-48's use a Hyd Cam, 4bbl Qjet, Cast pistons, 2 bolt main caps, "Pink" Rods, #0014 Blocks & #993 heads. Power output ranges from 300HP(gross) down to 175HP(net).

The L48 was the standard engine in the 1971 Chevrolet Corvette. It produced 270 hp (201 kW) and 360 lb·ft (488 N·m) with an 8.5:1 compression ratio.

The 1976-1979 L48 was the standard Corvette engine and produced 180 hp (134 kW) and 270 lb·ft (366 N·m). The 1980 L48 stood at 190 hp (142 kW) and 280 lb·ft (380 N·m) from 8.2:1 compression.

In 1972 the only way to get a L48 (4bbl V8) in a Chevy Nova was to get the Super Sport Package. This is indicated by the 5th digit in the VIN being a "K". 1972 was the only year you could verify the Super Sport package by the VIN.

In 1973 the "L-48" had cold air induction (throttle activated) and developed 190 hp (142 kW) (net). Beginning in 1974 the hp was reduced for several years until it reached a low of 165 hp (123 kW) (net) in 1975, before rising again.

L82

Years: 1973-1980

The 1973-1974 L82 was a "performance" version of the 350 producing 250 hp (186 kW) and 285 lb·ft (386 N·m) from 9:1 compression. It was down to 205 hp (153 kW) and 255 lb·ft (346 N·m) for 1975. It was the optional engine again in 1976-1977, producing 5 hp (4 kW) more. The 1978 L82 recovered somewhat, producing 220 hp (164 kW) and 260 lb·ft (353 N·m), and then 5 hp (4 kW) and 10 lb·ft (14 N·m) more for 1979. 1980 saw yet another 10 hp (7 kW) and 15 lb·ft (20 N·m).

L81

Years: 1981

The L81 was the only 5.7 L (350 cu in) Corvette engine for 1981. It produced 190 hp (142 kW) and 280 lb·ft (380 N·m) from 8.2:1 compression, exactly the same as the 1980 L48, but added computer control spark advance, replacing the vacuum advance.

L83

Years: 1982, 1984

The 1982 L83 was again the only Corvette engine (and only available with an automatic transmission) producing 200 hp (149 kW) and 285 lb·ft (386 N·m) from 9:1 compression. This was again the only engine on the new 1984 Vette, at 205 hp (153 kW) and 290 lb·ft (393 N·m). The L83 added Cross-Fire Fuel injection (twin throttle-body fuel injection). Since GM did not assign a 1983 model year to production Corvettes, there was also no L83 for 1983.

L98

For the new Generation IV V8, see GM L98.

Years: 1985-1992

The new 1985 L98 added tuned-port fuel injection "TPI", which produced 230 hp (172 kW) and 330 lb·ft (447 N·m). It was standard on all 1985-1991 Corvettes (rated at 230 hp (172 kW)-250 hp (186 kW) and 330 lb·ft (447 N·m)-350 lb·ft (475 N·m)). Optional on 87-92 Chevrolet Camaro & Pontiac Firebird models (rated at 225 hp (168 kW)-245 hp (183 kW) and 330 lb·ft (447 N·m)-345 lb·ft (468 N·m)) 1987 versions had 10 hp (7 kW) and 15 lb·ft (20 N·m) more thanks to 9.5:1 compression. Compression was up again in 1991 to 10:1 but output stayed the same.

LM1

The LM1 is the base 5.7 L (350 cu in) with a 4-barrel carburetor (usually with a Rochester Quadrajet) in passenger cars until 1988. Throughout its lifespan, it received either a points, electronic, and/or computer-controlled spark system, to conventional and feedback carburetors.

LM1s were superseded with the LO5 powerplant after 1988.

L05

The L05 was introduced in 1987 for use in Chevrolet/GMC trucks in both the GMT400 (introduced in April 1987 as 1988 models) and the R/V series trucks such as the K5 Blazer, Suburban, and rounded-era pickups formerly classed as the C/K until 1996 which includes chassis cabs and 4-door crew cabs. Although usage was for trucks, vans, and 9C1-optioned Caprices, the L05 was also used with the following vehicles:

  • 1992/1993 Buick Roadmaster sedan and station wagon
  • 1991/1992 Cadillac Brougham (optional engine)
  • 1993 Cadillac Fleetwood
  • 1992/1993 Chevrolet Caprice Wagon (optional engine)
  • 1993 Chevrolet Caprice LTZ
  • 1992 Oldsmobile Custom Cruiser Wagon (optional engine)

L05 usage was replaced by the GM LT1 after 1993 in GM B platform until production ceased in 1996.

In mid 1996 the L05 was equipped with Vortec heads used in the 1996 G30.

L31

The L31 replaced the LO5 in 1996 - known as the Vortec 5700. Known as the GEN 1+, this was the final incarnation of the 1955-vintage small block, ending production in 2005 with the last vehicle being a Kodiak/Topkick HD truck. Volvo Penta and Mercury Marine still produces the L31. The "MARINE" intake is a potential upgrade for L31 trucks.

See also

From the 1950s through the 1970s, each GM division had its own V8 engine family. Many were shared among other divisions, but each design is most-closely associated with its own division:

GM later standardized on the later generations of the Chevrolet design:

References

www.chevy-wiki.com

GM LS engine

The LS series is a new design intended as the only V-8 engine utilized in General Motors Corporation' line of RWD cars and trucks. The LS series was a clean sheet design with little in common with the classic Chevrolet small block V8. The LS is all-Aluminum and has 6-bolt main Bearing caps.

The LS engine has been the sole powerplant of the Chevrolet Corvette since 1997 and has seen use in a wide variety of other General Motors vehicles, ranging from Pontiac Firebird to full size trucks. Due to the engine's relatively compact external dimensions compared to its displacement and power output, the engine family is also a popular choice for Kit car, Hot rod and even Light aircraft.

Generation III

The Generation III V-8 engines replaced the LT family in 1997. These shared the same Bore spacing (4.4") as their Cast iron predecessors but almost everything else was changed. The bore was reduced to 3.9 in and the Stroke longer at 3.62 in. The engine blocks were cast in aluminum for car applications, and iron for most truck applications (notable exceptions include the Chevrolet TrailBlazer). The engine also introduced Distributor ignition. The traditional five-bolt pentagonal cylinder head pattern was replaced with a square four-bolt design, and the pistons are of the flat-topped variety. The cylinder Firing order was changed to 1-8-7-2-6-5-4-3, so that the LS series now corresponds to the firing pattern of other modern V8 engines (for example the Ford Modular engine).

LS1

GM LS1 engine from the Chevrolet Camaro

The LS1 shares little other than similar displacement, external dimensions, and rod bearings, with its predecessor. It is an all-aluminum 5.7 L (5,665 cc/345.7 cu in) Pushrod engine and was rated between 305 - 350 hp (227 to 261 kW) and 335-375 ft·lbf (454-508 N·m) of Torque in North America, depending on the application. In Australia, continuous modifications were made to the LS1 engine throughout its lifetime, reaching 382 hp (285 kW) in the Holden Special Vehicles YII series and a Callaway Cars Incorporated modified version, named C4B, was fitted to HSV GTS models producing 402 hp (300 kW).

The version fitted to the 2004 Pontiac GTO was rated at 350 hp (261 kW) and 365 ft·lbf (494 Nm) of torque. Beginning in 2001, the LS1 in the Corvette received the higher-flowing intake from the LS6 and a milder Camshaft to keep power at the same level; this also allowed GM to remove the Exhaust gas recirculation (EGR) system (Camaro/Firebird only; 97-00 Corvette LS1 never used an EGR system). The block is very similar to that of the higher-output LS6; beginning in 2002, some LS1 engines were actually built using the LS6 block instead. The LS1 was on the Ward's 10 Best Engines list for 1998.

  • 1997-2004 Chevrolet Corvette C5, excluding Z06
  • 1998-2002 Chevrolet Camaro Z28, SS
  • 1998-2002 Pontiac Firebird Formula, Trans Am, Trans Am WS6
  • 2004 Pontiac GTO
  • 1999-2005 Holden Commodore Ute
  • 1999-2005 Holden Commodore (Holden VT Commodore, Holden VX Commodore, Holden VY Commodore, Holden VZ Commodore)
  • 1999-2005 Holden Statesman (Holden WH Statesman, Holden WK Statesman, Holden WL Statesman)
  • 1999-2005 Holden Caprice (Holden WH Caprice, Holden WK Caprice, Holden WL Caprice)
  • 1999-2004 Holden Special Vehicles (all V8 models)
  • 2001-2005 Holden Monaro CV8
  • 2006-2007 Elfin MS8 Streamliner

LS6

GM LS6 engine in a Chevrolet Corvette Z06 LS6 can also refer to a 454 CID Chevrolet Big-Block engine of the 1970s

The LS6 is a higher-output version of GM's LS1 engine and retains the same capacity. The initial 2001 LS6 produced 385 hp (287 kW) and 385 ft·lbf (522 N·m), but the engine was modified for 2002 through 2004 to produce 405 hp (302 kW) and 400 ft·lbf (542 N·m) of torque. The LS6 was originally only used in the high-performance C5 Corvette Z06 model, with the Cadillac CTS V-Series getting the 400 hp engine later. The V-Series used the LS6 for two years before being replaced by the LS2 in 2006. For 2006, the Z06 replaced the LS6 with the new 7.0L LS7.

The LS6 shares its basic block architecture with the GM LS1 engine, but other changes were made to the design such as windows cast into the block between cylinders, improved main web strength and bay to bay breathing, an intake manifold and MAF-sensor with higher flow, a camshaft with higher lift and more duration, a higher compression ratio and a revised oiling system better suited to high lateral acceleration. [1]

The casting number, located on the top rear edge of the block, is 12561168.

Applications:

  • 2001-2004 Chevrolet Corvette C5 Z06
  • 2004-2005 Cadillac CTS V-Series

Generation IV

In 2004, the Generation III was superseded by the Generation IV. This category of engines has provisions for high-displacement ranges up to 7.0 L and power output to 638 hp (476 kW). Building upon the Generation III design, Generation IV was designed with Displacement on demand in mind, a technology that allows 4 cylinders in alternating fashion from side to side and front to back to be deactivated. It can also accommodate Variable valve timing. A 3-Poppet valve per cylinder design was originally slated for the LS7, which would have been a first for a GM Pushrod engine; but the idea was shelved owing to design complexities and when the same two-valve configuration as the other Generation III and IV engines proved to be sufficient to meet the goals for the LS7. It has been reported that the LS3 and an upcoming 6.0 L Vortec engine represent the final two designs to be considered in the Generation IV engine family, and that future designs — expected around 2009 — will be part of the Generation V engine family.[2]

LS2

GM LS2 engine in a 2005 Chevrolet Corvette

The LS2 was introduced as the Corvette's new base engine for the 2005 model year. It produces 400 hp (298 kW) at 6000 rpm and 400 ft·lbf (542 N·m) at 4400 rpm from a slightly larger displacement of 6.0 L (5,967 cc/364.1 cu in). It is similar to the high-performance LS6, but with an improved power peak and more torque throughout the rpm range. The LS2s in the E-series HSVs are modified in Australia to produce 412 hp (307 kW) and 412 ft·lbf (559 N·m). The LS2s in the Buick Rainier, Chevrolet Trailblazer SS, and the Saab 9-7X Aero are rated at 395 hp (295 kW) and 400 lb·ft (540 N·m) of torque.

Applications:

L76

See also the Vortec 6000 L76

L76 was originally Holden's version of the 6.0 L (5,967 cc/364.1 cu in) Generation IV engine. While displacement on demand technology was disabled on Holdens, this feature is enabled on the 2008 Pontiac G8 and subsequently re fitted in the 2009 model Holdens with AFM enabled, but only on models fitted with the 6L80 Automatic Transmission. The engine also meets Euro III emissions requirements. Output is 348 hp (260 kW) at 5600 rpm and 376 ft·lbf (510 N·m) at 4400 rpm for the Holden variant, and 361 hp (269.8 kW) and 385 ft·lbf of torque (526.5 N·m) for the G8 GT.[3]

Applications:

  • 2006 Holden VZ Commodore
  • 2008 Pontiac G8
  • 2009 Holden VE Commodore
  • 2009 Holden WM Statesman / Holden WM Caprice
  • 2009 Holden VE UTE

L98

For the tuned-port Generation I engine of the same RPO, see Chevrolet L98

The L98 is a slightly modified version of the L76. Since Holden does not use displacement on demand, some redundant hardware was removed from the L76. Power increased to 362 hp (270 kW) at 5700 rpm and 391 ft·lbf (530 Nm) at 4400 rpm.

Applications:

  • 2006 (MY06) Holden VZ SS Thunder Ute
  • 2006-2007 Holden VE Commodore
  • 2006-2007 Holden WM Statesman / Holden WM Caprice
  • 2007-2008 Chevrolet Lumina SS
  • 2007-2008 Chevrolet Caprice SS

LS3

GM LS3 Engine in a 2008 Chevrolet Corvette LS3 can also refer to a 402 CID Chevrolet Big-Block engine of the 1970s

The LS3 was introduced as the Corvette's new base engine for the 2008 model year. It produces 430 hp (320 kW) at 5900 rpm and 424 ft·lbf (575 N·m) at 4600 rpm without the optional Corvette exhaust and is SAE certified. The block is an updated version of the LS2 casting featuring a larger bore of 4.06 in (103 mm) creating a displacement of 6.2 L (6,162 cc/376.0 cu in). It also features higher flowing cylinder heads sourced from the L92, a more aggressive camshaft with 0.551" lift, a revised valvetrain with 6 mm (0.24 in) offset intake rocker arms, a high-flow intake manifold and 47 lb/hr fuel injectors from the LS7 engine.

The L76/L92/LS3 cylinder heads use 2.165 in (55.0 mm) intake valves, and 1.59 in (40 mm) exhaust valves. Improved manufacturing efficiency makes these heads cheaper than the outgoing LS6 heads, and severely undercuts aftermarket heads. The large valves, however, limit maximum rpm - 6000 in the L76 (with AFM), and 6600 in the LS3 (with hollow stem valves).

In addition to the above, a dual mode exhaust package with a bypass on acceleration is available. The dual-mode exhaust uses vacuum-actuated outlet valves, which control engine noise during low-load operation, but open for maximum performance during high-load operation. The system is similar to the C6 Z06, but uses a 2.5 in (64 mm) diameter exhaust compared to the Z06's 3 in (76 mm). Power is boosted to 436 hp (325 kW) and 428 ft·lbf (580 N·m) with this option.

From April 2008, Australian performance car manufacturer, HSV, adopted the LS3 as its standard V8 throughout the range, replacing the LS2. The LS3 received modifications for its application to HSV's models, producing 425 hp (317 kW). Power and torque was restricted to protect the drivetrain currently used in the E-Series sedans.

Applications:

  • April 2008-present Holden Special Vehicles (all V8 models)
  • 2008-present Chevrolet Corvette
  • 2009 Pontiac G8 GXP (source: Pontiac web site, "Upcoming Vehicles," 3-16-2008)
  • June 2008-present Vauxhall VXR8
  • 2010 Chevrolet Camaro
  • The show Top Gear used the LS3 to power a blender.[4]

L99

For the 4.3 L (260 cu in) Generation II engine of the same RPO, see GM LT Engine

The L99 is derived from the LS3 with reduced output but adds Active Fuel Management (displacement on demand), which allows it to run on only four cylinders during light load conditions.[5] Power is 400 hp (298 kW) and 395 ft·lbf (536 N·m) of torque.[6][7]

Applications:

LS4

5.3 L LS4 V8 in a 2006 Chevrolet Impala SS LS4 can also refer to a 454 CID Chevrolet Big-Block engine of the 1970s

The LS4 is a smaller 5.3 L (5,328 cc/325.1 cu in) version of the Generation IV block. Though it has the same displacement as the Vortec 5300 LH6, it differs in that it has an aluminum block rather than an iron one and it uses the same cylinder head as the Generation III LS6 engine.

This engine is adapted for Transverse engine Front-wheel drive applications. According to GM, "The crankshaft is shortened 13 mm – 3 mm at the flywheel end and 10 mm at the accessory drive end – to reduce the length of the engine compared to the 6.0L. All accessories are driven by a single serpentine belt to save space. The water pump is mounted remotely with an elongated pump manifold that connects it to the coolant passages. Revised oil pan baffles, or windage trays, are incorporated into the LS4 to ensure that the oil sump stays loaded during high-g cornering." [8] Active Fuel Managemment is also used. Output of this version is 303 hp (226 kW)/300 hp on LaCrosse Super and 323 ft·lbf (438 N·m).

Applications:

LS7

7.0 L LS7 engine in a 2006 Chevrolet Corvette Z06 LS7 can also refer to a 454 CID Chevrolet Big-Block engine of the 1970s

The LS7 is a 7.0 L (7,011 cc/427.8 cu in) engine, based on the Gen IV architecture. The block is changed, with sleeved pistons and a larger 4.125 in (104.9 mm) bore and longer 4.00 in (101.6 mm) stroke than the LS2. The small-block's 4.4 in (111.8 mm) bore spacing is retained, requiring pressed-in cylinder liners. The crankshaft and main bearing caps are Forged steel for durability, the connecting rods are forged titanium, and the pistons are Hypereutectic piston. The two-valve arrangement is retained, though the titanium intake valves by Del West have grown to 2.20 in (55.9 mm) and sodium-filled exhaust valves are up to 1.61 in (40.9 mm).

Peak output is 505 hp (377 kW) at 6300 rpm and 470 ft·lbf (637 N·m) at 4800 rpm with a 7000 rpm Redline setting a new record for a production overhead valve pushrod engine. During GM's reliability testing of this engine in its prototype phase, the LS7 was remarked to have been repeatedly tested to be 8000 rpm capable, although power was not made at that rpm level, due to the constraints of the camshaft's profile and the intake manifold ability to flow required air at that engine speed.

The LS7 is hand-built by the General Motors Performance Build Center in Wixom, Michigan. Most of these engines are installed in the Z06, but some are also sold to individuals by GM as a Crate engine.

After an extensive engineering process over several years, Holden Special Vehicles fitted the LS7 to a special edition model, the HSV W427. The HSV-tuned engine produces 375kW (503hp) and 640Nm, making it the most powerful car ever built in Australia. The W427 was unveiled at the Melbourne International Motor Show on the 29th February, 2008[9] and went on sale in August 2008.

Applications:

  • 2006-2008 Chevrolet Corvette Z06
  • 2008 HSV W427

LS7.R

The LS7.R engine is a variation of the LS7 used in the highly successful C6.R American Le Mans Series racecar. It was crowned as Global Motorsport Engine of the Year by a jury of 50 race engine engineers on the Professional Motorsport World Expo 2006 in Cologne, Germany.

LSX

At the 2006 SEMA show, GM Performance Parts introduced the LSX engine, an all-new cast-iron racing block based on the LS7 engine. It was designed with help from drag racing legend Warren Johnson. It offers displacements ranging from 364 cubic inches to 511 cubic inches (4.25" Bore x 4.5" Stroke) and is capable of withstanding 2500 bhp. This block incorporates two extra rows of head-bolt holes per bank for increased clamping capacity. The six bolt steel main caps are the same ones used on the LS7 engine. The engine debuted at the auto show in a customized 1969 Camaro owned by Reggie Jackson. The LSX will be available starting the second quarter of 2007, set to be available in authorized dealerships and retailers on March 31, 2007.[10]

LS9

The LS9 is a 6.2 L (6,162 cc/376.0 cu in) supercharged engine, based on the LS3; the LS7 block was not used due to the higher cylinder pressures created by the supercharger requiring the thicker cylinder walls of the LS3. Cylinder dimensions are now 4.06 in (103.25 mm) bore with a 3.62 in (92 mm) stroke. It is equipped with an Eaton four-lobe Roots type supercharger. Power output is 638 hp (476 kW) at 6500 rpm and 604 lb·ft (819 N·m) of torque at 3800 rpm.

Applications:

  • 2009 Chevrolet Corvette ZR1

LSA

The supercharged 6.2 L LSA is similar to the LS9 and scheduled to debut in the 2009 Cadillac CTS-V. The LSA has been SAE certified at 556 hp (415 kW) @ 6100rpm and 551 lb·ft (747 N·m) of torque @ 3800rpm. GM labels it "the most powerful ever offered in Cadillac’s nearly 106-year history". The LSA features a smaller 1.9 L capacity supercharger rather than the 2.3 L variant of the LS9. Other differences include a slightly lower 9.0:1 compression ratio, single unit heat exchanger and cast pistons.

Applications:

  • 2009 Cadillac CTS V-Series

Vortec engines

Versions of both the Generation III and Generation IV V8 have also been used in trucks and SUVs. These are usually branded as GM Vortec engines.

Problems

In the early production run of the LS-series engine, some engines encountered abnormal amounts of 'piston slap' - a problem caused by too much clearance between the cylinder bore and the piston. [11] 'Piston Slap' sometimes sounds more like a knock or the sound of a Diesel engine running, it is also typically worse when the engine is cold and lessens as the engine reaches operating temperature. The noise of 'Piston Slap' often is louder when listening for it below the Oil pan.

See also

References

  • LS1 article at AutoSpeed
  • LS2 article at AutoSpeed
  • LS1Tech Forums

www.chevy-wiki.com


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