454 vibration
 

I have a 1970 Chevelle with a 454 , just converted it to a TKX 5 speed Manuel it was a 700R4, now I am getting a vibration at 1600 RPM and higher sitting in drive way clutch in or out doesn't change vibration so thinking its flywheel? fly wheel is external balance but not sure on the 2 piece rear seal if I have wrong flywheel. had a Chevy dealer install with my MDL kit
thanks for any input
Steve

There were Externally balanced and internally balanced. Mine is internal. But yes that is probably what it is something dont match.

Check to see if it was which type by casting number. Then the wild card did anyone ever work on it and change the crankshaft.

Easiest way is get the old flexplate and see which type it is. It worked with that one.

numbers say its an early 70's 454, flex plate removed has a big weight on it

Okay this is what I found. the 400 sb and the 454 flywheels have the same casting number but are balanced differently.

They are saying there are no aftermarket internally balanced engines. Trust me they are wrong. I got one. Just got to order the right crankshaft they make them.

Sounds to me like take the one you got and the original and spin them see if they are the same.