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While most General Motors divisions simply created tall-deck versions of their V8 engines, Chevrolet created a new big-block design for large-displacement use. Cadillac also had a special big-block design.
Generation 1
The first big-block V8 family from Chevrolet was introduced in 1958 and produced through 1965. It was used in Chevrolet cars and trucks.
348
The first big-block, by GM's reckoning, was the 1958 348 in³ used in full-size Chevrolet trucks.
409
The company later produced 409 in³ and 366 in³ variants before settling on the 427 in³ also used in cars.
Generation 2
Development of the automobile big-block started with the Mystery Motor used in Chevrolet's 1963 Daytona 500 stock cars. The secret motor was released in 1965 as the Mark IV, and it was the dual-plane placement of the valves that was the key to its performance. The new "big-block" was used by Chevrolet and GMC trucks. Production of this generation of engines ended in 1976.
396
The 396 in³ (6.5 L) V8 was introduced in the 1965 Corvette as the L78 option. It had larger bore and stroke at 4.094 in by 3.76 in (104 mm by 96 mm) than any previous small-block and produced an amazing 425 hp (317 kW) and 415 ft.lbf (563 Nm).
402
427
The huge 427 in³ (7 L) V8 was introduced in 1966 on the Corvette. Bore was up to 4.25 in, and the power ratings were said to be conservative. The hydraulic-lifter L30 (L36 in 1968) option was rated at 390 hp and 460 ft.lbf (624 Nm), while the solid-lifter L72 pushed out 425 hp (317 kW) and 460 ft.lbf (624 Nm). The 1967 L89 (1968 L71) bumped this up to 435 hp (324 kW) and 460 ft.lbf (624 Nm), while the L88 from the same years produced 560 hp (418 kW).
The 1969 ZL1 is one of the best-remembered big-blocks. Putting out 430 hp (321 kW) and 450 ft.lbf (610 Nm) from a special camshaft and tuned Holley carb in an aluminum intake, it was a $2000 option! But the all-aluminum engine block weighed just 98 lbs, less than half the weight of a similar iron block. Just two production Corvettes were made with this option, making it one of the rarest.
The 427 was also used in GM full-size trucks.
454
The big-block was expanded again for 1970 to 454 in³ (7.4 L) with a 4.251 in (108 mm) bore and 4 in (102 mm) stroke. The 1970 Corvette LS5 engine produced 390 hp (291 kW) and 500 ft.lbf (678 Nm). There was a one-off LS7 which was tuned for performance, with 465 hp (347 kW) and "just" 490 ft.lbf (664 Nm).
Power began falling off after 1970, with the 1971 LS5 producing 365 hp (272 kW) and 465 ft.lbf (630 Nm), and the new LS6 option coming in at 425 hp (317 kW) and 475 ft.lbf (644 Nm). Only the LS5 remained in 1972, now at just 270 hp (201 kW) and 390 ft.lbf (529 Nm). The 1973 LS4 was at 275 hp (205 kW) and 390 ft.lbf (529 Nm), with 5 hp (4 kW) and 10 ft.lbf (14 Nm) gone the next year. 1974 was the last year of the 454 in the Corvette.
GM continued to use the 7.4 L 454 in their truck line, introducing a new Vortec 7400 version in 1991.
8100
A substantially-modified version of the 454 is sold today as the Vortec 8100.
External links
- Nasty Z28 (http://www.nastyz28.com/camaro/z27396.html)
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:
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