Corvette Small-Blocks - 10 To The 8th Power

Part 2: An illustrated look at 10 of Chevy’s most significant Corvette small-blocks

Christopher R. Phillip Mar 8, 2012 0 Comment(s)
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The Corvette small-block's nine-finned aluminum rocker-arm covers were die cast by the Hoover vacuum company.


Displacement 283 ci

Compression 9.5:1 (standard), 10.5:1 (optional)

Bore x Stroke 3.87- x 3.00-in

Fuel System Carter Wrought Cast Four Barrel (WCFB) carburetor (standard); two Carter Wrought Cast Four Barrel (WCFB) carburetors or fuel injection (optional)

Horsepower/Torque (lb-ft) 245/300 (standard); 250/285, 270/305, or 283/290 (optional)

Cam Hydraulic-lifter, 300/300-deg duration, 0.398/0.398-in lift (standard); "Duntov" solid-lifter, 287/287-deg duration, 0.394/0.400-in lift (optional)

Did you know? There were six factory speed options for Corvettes in '57: RPO 469A and 469C featured the 2x4 carburetion from the previous model year ("A" designated a hydraulic cam, and "C" specified a solid-lifter cam) and were rated at 250 hp and 270 hp, respectively. RPOs 579A, B, C, and D featured fuel-injection ("A" and "C" had hydraulic lifters and were rated at 250 hp; "B" and "D" had solid lifters and were rated at 283 hp.)

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Late in the year, Hoover introduced the seven-fin rocker-arm cover, which cleared the air meter on the fuel-injected Corvettes, unlike the earlier-style covers.


Engine order codes L75, L76, L78, L79, L84 (shown)

Displacement 327 ci

Bore x Stroke 4.00- x 3.25-in

Fuel System Carter AFB four-barrel (standard); Holley four-barrel or Rochester fuel injection (optional)

Horsepower/Torque (lb-ft) 250/350 (standard); 300/360 (L75), 365/350 (L76), 375/352 (L84) (all optional)

Cam Solid-lifter, 300/300-deg duration, 0.398/0.398-in lift (standard); solid-lifter, 342/342-deg duration, 0.447/0.447-in lift, or solid-lifter, 346/346-deg duration, 0.485/0.485-in lift (optional "Duntov 0.030/0.030")

Did you know? Model-year 1965 was the fourth year of the 327 and the second year of both the larger-valve (2.02/1.60) heads and the Duntov 0.030/0.030 camshaft, which earned its nickname from the recommended valve lash adjustment. It was the fourth and final year of the second-generation Rochester mechanical fuel injection. The L76 once again received a high-rise aluminum intake manifold.

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Gen II (1992-1996)


Engine order code LT1

Displacement 350 ci

Compression 10.4:1

Bore x Stroke 4.00- x 3.48-in

Fuel System Electronic sequential-port fuel injection

Horsepower/Torque (lb-ft) 300/340

Cam Hydraulic roller, 279-/276-deg duration, 0.447/0.459-in lift

Did you know? The LT1 was the first architectural redesign of the Chevy small-block engine. It featured reverse-flow cooling with a gear-driven water pump, in which the heads were cooled before the block; a fully solid-state distributor (the Optispark), which was relocated from behind the intake manifold to the front of the timing cover and was driven by the camshaft; and aluminum cylinder heads. All LT1s installed in Corvettes left the factory with Mobil 1 synthetic oil, which eliminated the need for a separate oil cooler.

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Gen III (1997-2004)


Engine order code LS1

Displacement 346 ci

Bore x Stroke 3.90- x 3.62-in

Compression 10.25:1

Fuel System Electronic sequential-port fuel injection

Horsepower/Torque (lb-ft) 345/350

Cam Hydraulic roller, 198-/209-deg duration (at 0.050), 0.500/0.500-in lift

Did you know? The LS1 heralded the Chevy small-block's third generation, though its only noticeable resemblances to the '55 edition were its shared 4.40-inch bore spacing and two-valve pushrod design. The "Gen III" engine's clean-sheet redesign relied heavily upon computational fluid dynamics (CFD) and finite- element analysis (FEA) electronic engineering tools. It featured the Chevy small-block's first use of a deep-skirt block, cross-bolted main-bearing caps, forged powdered-metal connecting rods, investment-cast-steel needle-bearing rocker arms, beehive valvesprings, equal-length intake ports, a composite- material intake manifold, and electronic throttle control. The firing order changed to 1-8-7-2-6-5-4-3.

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Engine order code LS6

Displacement 346 ci

Bore x Stroke 3.90- x 3.62-in

Compression 10.5:1

Fuel System Electronic sequential-port fuel injection

Horsepower/Torque (lb-ft) 405/400

Cam Hydraulic roller, 204-/211-deg duration (at 0.050), 0.525 /0.525-in lift

Did you know? The 385hp LS6 was considered a work in progress when it was released in '01. For the next model year, GM engineers fitted the LS6 with a higher-lift cam and a larger outlet for the air-cleaner housing. They also eliminated the mass airflow sensor's honeycomb diffuser, helping push the powerplant's horsepower rating to 405 in '02-'04.

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Gen IV (2005-present)


Engine order code LS7

Displacement 427 ci

Bore x Stroke 4.125- x 4.00-in

Compression 11.0:1

Fuel System Electronic sequential-port fuel injection

Horsepower/Torque (lb-ft) 505/470

Cam Hydraulic roller, 211-/230-deg duration (at 0.050), 0.588-/0.593-in lift

Did you know? The LS7--the first production 427ci powerplant under a Corvette hood in 37 years--is the first Chevy production small-block to feature a 7,000-rpm redline, titanium connecting rods and intake valves, and hand-built assembly. A three-valve-per-cylinder design was planned, which would have been another first for the Chevy small-block, but was cancelled.

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