Thread: 396 375hp build question

Tweet

The 375 HP 396 was the L-78 motor, with mechanical-lifter cam, large-port iron heads, 11:1 compression ration, 4-bolt mains, forged Tuftrided crank and forged pistons. 11:1 on the street today is a problem because of detonation.

The cam timing was 40-86/88-38 (306/306 duration at 0 lift), with .500/.500 lift. (Casting #3863143)

You've got the same block used in the L-78, but not the heads. The heads you have were used on the 396/275 HP LS-3 engine, have a larger combustion chamber and smaller valves.

Here's a link to a page with the full L-78 and LS-3 specs.
http://www.nastyz28.com/camaro/z27396.html

Cam grinders make reproductions of the cam, but there are probably better grinds out there for what you have.

I can tell you what you have, and what the L-78 had, but there are other folks who can tell you how to build a strong engine with your parts. Erik Erikson or Pat McCarthy.

Myself, I'd be wary of duplicating an engine for the street with solid lifters and an 11:1 compression ratio. You can get massive HP out of a BBC without going that direction. Get down around 9 to 9.5:1 with your heads and pick a good hydraulic cam, and you can get your 375 hp easily.