explorer 8.8 in an a-body: experience needed

Um I'm sure that anyone will say this. If your 8 3/4 is toast that 8.8 wont hold up. Maybe if its properly set up and prepped but not a chance stock.
I've never rebuilt one, but it would seem to be better to rebuild the one you have then to put a PHORD part in it, what went south?? gears?? posi?? both?? just my .02