All my search found was an old GM part number that was a dead end.
Here are the specs:
8 bolt holes, 0.500" in diameter each
Approx. 4.700" outside diameter
Approx 2.900 - 3.100" inside diameter
This is the old gasket dimensions.
The adjusting nut and washer are just standard hardware without a seal. This is the same type gasket as any other full floating rear I have done, just with different dimensions.
