394 vs 303,324,371 engines

[pontiac1953]

in the oldsmobile general forum, chequenman is telling me that the block and head angle is different on a olds 394, is this true ?, i don't see how, all were 90 degree V8 engines. i have owned a 1950 303, two 1957 371's with J2, and a 1960 371, so i have never own a 394, but i have seen so many of them over the years, and i see no machining different that a 394 is so different from the earlier rocket V8's. is it not interchangeable so that a 57-58 olds J2 set wouldn't fit on a 394 ? charles coker, 1953 pontiac tech advisor.

[Steve Westlake]

Hi Charles, Chequenman is correct in stating that the intakes don't interchange. I have a offenhauser J-2 from a 57 and it doesn't fit any of my 63 394 engines so it sits on my shelf until I get a 57 98 and add it.

The changes are slight but enough to give you to much gap and the intake doesn't line up with the intake ports on the heads.

The offenhauser manifold is being reproduced now for the 394 and sell for around 400 bucks, I missed one at spring Carlisle that sold for 200 bucks to a guy with a 64 394 in a hot rod from texas.

Steve

[F&J]

A J2 won't fit a 324 or 303 either, without planing the flanges. That's because the deck height was raised in 57...so then the intake is slightly wider.

[Guest rsd9699]

So you end up with 3 very distinct engine groups where the parts look the same but are not.

Crankshafts are also tricky depending on the transmission they were attached to in the same year.

Ron