There is an oddball flange out there that Im not sure what it came from exactly. Its basically a square version of the 84+ flanges. It doesnt fit the CV flange or any other that Ive run across.
You can either drill the flange to have the correct pattern or swap it with your old rear end.
yea i have one of the weird things, the holes are the right size and all but its like they drilled 9 oclock and 3 oclock then moved the flange a bout 5 degrees and then drilled 6 oclock and 12 oclock