I've been going through all the threads without much luck. What is the usual headmark on the balancer bolt? And did it have a lock washer or a star washer? In the AIM it looks to be a star washer.
My 69 Z28 has "TR" headmark with a star washer, it is also drilled as though safety wire could be used. Owned the car since 74.
FWIW. I have seen this drilled balancer bolt before on lots of high HP Corvette and Z28 engines. Also seen "WB" head marking.
Hope this Helps.
Well, I have one that says TR and one that says Rockford. I know I got a repro one once and it stripped out so I wanted to make sure I didn't use that one again.