Engine Rebuild

Q: Engine Rebuild

My new 1968 firebird 400 is burning oil on start up. I think I’ve got some time left before she’s real bad. So I’m starting my research now on rebuilding my motor. There’s several issues that have come up and I would like some clarification…If you can…

1) I have been told that a chevy engine will not fit the bell mountings and that the motor I most likely have…the original…is an oldsmobile engine…is that true?

2) I’d like to rebuild myself…I found pistons, valve rods in the yearone catologe…but no gaskets, rings. Is there a better engine rebuild source out there? Will a chevy rebuild kit work?

3) If I have cylinders reamed, will I need new pistons?

4) My chilton manual say there are oversized valves available for use in bored out valve guides. Is that true…where do I get em?

5) If I add high performance cam will I need different valves and valve rods and lifters?

6) If I change pistons to lightweight, and add a high performance cam is that still stock…you can’t see those items.

A: In short answer form:

1) True. Chevy uses a different bolt pattern for bell house mounting. The Pontiac uses what is called the BOP (Buick-Oldsmobile-Pontiace) bolt pattern, Cheby is …well, Chevy. The Pontiac 400 is Pontiac specific. Not the same as any other 400 by anyone. Only Pontiac parts fit.

2) See answer 1) Check PAW Atuparts Catalogue, Summitt Auto Parts.. Check into any hot rod type magazine to locate rebuild parts. Very common stuff..

3) If you “ream” The cylindes, I assume you mean reaming the ridge at the top of the cylinder. No new pistons are required. If, however, you mean to HONE or OVERBORE the cylinders, then new pistons are needed.

4) Maybe. It depends on the cam. Each cam manufacturer has recommendations. If you stay streetable, then stockers willprobably work fine. If you want something special,……. You have to pay to play.

5) Usually, stock means stock, from the factory. If you are referring to STOCK class at the dragstrip, the sponsoring raceing organization has a set of rules that define exactly what stock is. In NHRA stock class, some aftermarket cams are still considered stock. Lightweight pistons are usually not stock. If you are referring to street or bracket racing… Well what ever is under the hood is whatever you say is under the hood. Caveat Emptor! Let the Racer beware! *smiles*

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