I just seen a 8.75 on Facebook Mopar Page, a guy has a complete rear for an a body with new rear drums, for a $1000 he will ship also.
Deals are out there if you are patient.
To the OP, I would just rebuild what you have and add a suregrip to it.
I had a stock rebuilt 318 with a 4BBL and headers in my 70 swinger with a 7 1/4 peg leg. That rear end held up fine, daily driving it and making over 10 passes at the drag strip.
