Will a late model small block balancer that bolts on work on a older model that's pressed on without a bolt? I know you can drill the shaft, but I was wondering about the press fit. I know the timing mark is off too.
All the balancers will fit on the crank. The fit is the same.
What you need to pay attention to is the keyway vs. the TDC mark.
Up through 1968 engines, the timing mark is lined up with the keyway.
In 1969, when they went to the long water pump, the timing mark was put 10º CCW to the keyway. You can still use it, but you need to have the correct timing tab for teh balancer used. Either waiy you need to have the correct timing tab. There are bolt on tabs available.
There are also a few weird balancers out there with the TDC mark 30º CCW from the keyway.
Highly recommend tapping the shaft and using a bolt. did that on mine and worked well. Years ago I put a later model balncer on a 57 283 without tapping the end of the crank--came off within 5 miles of intial drive.