Had my motor(L98) rebuilt last year and had it upgraded to a 383. I noticed that I get a lil more vibration since the rebuild mainly around 1800-2000 rpm range at a stand still. My question is if the motor is out of balance would it vibrate at any rpm range, or would it just depend?

 

I don't have a good answer for you, sorry. But I'm local to you - sent you a PM.

 

No they either vibrate at low rpm like yours or if real bad they shake all the time. You said you have a 383 is it externally balanced or internally? You may have an externally balanced crank with stock internally balanced flywheel or balancer.

 

I had the wrong harmonic balancer on an old camaro I had and it would vibrate in the high rpm's but not in the low. The higher the rpms the worse it would vibrate. I got the right HB and the vibs went away.