Hi everyone- so I'm a converted Chevy guy with a 71 cutlass. Motor is a '70 455. Pulled to reseal and detail. Turns out its a 4 speed motor with a pilot bearing so that the route I'm going from auto.

My question is about flywheels. Are all 455 flywheels the same balance and are 350 and other flywheels compatable without a rebalance the the crank? From what I have read the olds flywheel does not have to be matched to the crank. They all have the same "factory balance"

All help and clarification is appreciated!!

 

I am a novice with engine building but my high performance built 455 was originally for an automatic car. So I bought an SFI flywheel I had a machine shop balance-match the 455 flexplate to the new flywheel for the Muncie set up. I know these are externally balanced motors and I could have wasted money ( not much) on this procedure but all is fine, no issues/vibrations-The motor was built and never started when I bought it. I had this work done before the motor was started and tuned on the dyno. Just an idea

 

All 68 and later Olds wheels are "Detroit balanced" the same. Aftermarket parts may or may be balanced to the precision that Olds used. Probably good enough for the street. The best would be to balance it, then install the pressure plate and make sure it is zero balanced and does not throw out the overall balance.

 

x2

 

If it is an original non rebuilt motor I would just throw a flywheel on it and not worry. If it has been rebuilt they may have drilled the flexplate to balance it. They shouldn't have but some shops do. In that case I would have the flywheel match balanced.

 

OK thanks everyone. Will a 350 olds flywheel work? I have access to one from a W-31. If they are all neutral balance I assume it will. However could they be offset balanced the same or different depending on which engine size the flywheel originally went with? I know the flywheel is tapped for both size clutches so I would think it would work properly on either engine.

 

350 flywheel should be just fine