My 69 SS long ago lost it's original big block, and the car came with a 350 small block (casting # 3970010). The guy I bought it from claimed it had a 400 crank and was therefore a "383 stroker motor". I am going to sell this motor but don't want to give a buyer bad info, so.......without tearing the motor apart or oil pan off, what is the easiest way to distinguish the 400 crankshaft? I seem to remember the harmonic balancers on the 400's were larger than the 350's...were the flywheels different?

Matt

I'd pull the pan. Anyone buying it will want to anyway. The block should have clearance spots ground on the rails for the crank.

Why don't you check what kind of balancer and flexplate the motor has on it. If it was a 400 crank it would be externally balanced wouldn't it. Check to see if there is an extra weight welded onto the flexplate. If it was a 400 crank and you had 350 balancing parts on it, the motor would have an unmistakable shake to it when you rev her up..

Alex D.
69 Chevelle SS 496ci

pull the pan-its the only way to know for sure-bal/flywheel could have been replaced, motor could have been int bal., as a buyer, you would have to prove it to me by meas. stroke, if i found out diff(like some ebay sellers) you would owe me money , bad deal all around-to many people selling stuff thats not what it should be