I thought it was a good US made one brand new maybe 500 miles ago, but with the new motor and a little extra weight in the car, I went to do a burnout and I took the caps clean off the joint. Its a conversion joint from the later model T10 to the 55 rearend.
I guess its time to put the 9" in.

55 Vicky & customline
58 Rack Dump, 55 F350 yard truck, 57 F100
59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?