You haven't mentioned a whine noise from that 7.25, only the clunk. That puzzles me. And that's why I suggested other sources of the clunk. A worn/overheating gear box should whine. Anyway.... Anything other than a small bolt pattern 7.25 from the a-body will require some change. A small bolt pattern 8.75 from a a-body will require drive shaft length change. 8.25 from a later model a-body will require wheel/bolt pattern change and drive shaft length change. A rear form something other than a-body will require spring perches moved along with some of the other changes.
So outside of finding a good used small bolt pattern 7.25 from a a-body, the 8.75 is the least complicated swap. That 8.75 a heavy duty/performance piece so hot-rodder's will pay a premium for them. Their deep pocket swaps can be where the good used 7.25 rear comes from. Good hunting
