Oldmanrick. The car originally had a 225 slant 6 and 3 speed manual trans. The third member housing has numbers 2070721. the ring gear has numbers 2070225 and 3.91-1 stamped on the side.
That's a 3.91 R&P used in a 20707(4)1 case. Maybe you just misread the number.....can be a little difficult at times. And it is a 8.75" rear.
I'm amazed that a /6 could have a original 3.91...even with the 3spd. Bottom line is, however it got there, you may already have something nice to build on. Not sure whether your damage was actually to the "housing" or just to the center section itself?
