Sounds like PO and you have done quite a bit, all the while that 7 1/4 remains??
Hands down a better rear end.
You want to spend more money to break it?
Not sure if that was directed at me but running the 7 1/4" was temporary, after a few years I had the money to rebuild and swap in a 1967 B-body 8 3/4" which is still in the car now. Also my ultimate goals with my car were quite a bit more race-oriented than the O.P.
