[chevy_mike]

Yeah, what Jimmy said.

When I did my 250, I drilled and tapped the hole before installing the balancer and was able to use a standard balancer installer instead of pounding it on. If I remember, didn't your old one have problems. Was the whole balancer sliding back and forth or was it just the outer ring? I don't recall. If the whole balancer was doing it, my guess is the snout wore down enough the new one is not tight once everything heats up.