I'm new to the sight. I'm looking for advice. I have 455 olds engine. I know it's a 73 or newer because of the intake manifold. It has dish pistons I know because it is tore down to short block. It also has j heads. I'm going to rebuild it. I would like to get 375hp. The olds motor is new to me. Help please.

 

Are you looking to do a complete rebuild, or just improve what you have? If your looking to improve what you have, is the short block sound? Decent oil pressure, no excess smoke or noises? If it passes the background check, your 375hp goal is pretty easy to achieve with heads and camshaft. Get some aftermarket aluminum heads, mill them to bump the compression, get a modern camshaft, good induction/exhaust, and dial in the ignition.

If your looking to rebuild, your goal is even easier. Bore the engine, install lightweight pistons without the enormous dish, careful quality machine work, and the above suggestions, and 425 would be the low side of what I would expect.

Find a machinist familiar with Oldsmobile engines. Good luxk

 

There are books on Olds engines, I like the one by Bill Travoto. Good info and advice. Especially on oil mods which he DOES NOT recommend. The Olds engineers did it right. Don't stop at the engine. Distributor, carb, and exhaust are critical to max performance. Do your research, find a good machinist, don't rush.