Chevy Big Block Engines

Generation I (“W” head)

348 in³ (5.7 L) 250 hp to 350 hp
4.125” (104.8 mm) X 3.25” (82.5 mm)
1958-1961 car, 1958-1965 truck

409 in³ (6.7 L) 360 hp to 409 hp ( Beach Boys Song)
4.312” (109.5 mm) X 3.50” (88.9 mm)
1961-1965 car only

Z11 427 in³ (7.0 L) 430 hp, 13.5:1 c.r., 2 x 4bl, under-rated, 600 hp est
4.312” (109.5 mm) X 3.65” (92.7 mm)
1963 (only 50 produced)


Generation II (RAT engine)

L78 396 in³ (6.5 L) 425 hp
4.094” (104 mm) X 3.76” (96 mm)
1965-1069

402 in³ (6.6 L) (Chevy kept the 396 name)
4.124” (105mm) X 3.76” (96 mm)
1970-1972

427 in³ (7 L) 390 hp to 560 hp
4.250” (108mm) X 3.76” (96 mm)
1966-1995 (car, truck, bus)

454 in³ (7.4 L) 270 hp to 465 hp
4.251” (108 mm) x 4” (102 mm)
1970-1995 (car, truck, bus)

More Info:
http://www.roadsters.com/bbc/


Generation III (Vortec series)

Vortec 7400 (7.4 L)
4.251” (108 mm) x 4” (102 mm)
1996-2000

Vortec 8100 (8.1L) 225hp to 340hp
107.95 X 111 mm
2001--

The Vortec 8.1 or 496 is 4.25 x 4.37 and i dont remeber any one being under 340 HP and 455tq