4lug to 5 lug rearend interchange

Yep...lots of 4 lug 8" rears out there.

 

The very vast majority of very late 1970 to '72 cars with 6 cylinders were 4 lug with 8 inch rears. Most 1970 model cars had the 7.5 that will break if you look at it wrong, but the very late production ones had the 4 lug 8 inch. They went to 5 lug on all Mavericks and Comets from '73 on.

 

Also if you are running old school wheels and want to squeeze as much tire as possible in there, 1980 and earlier Granada and Monarch rear axle assemblies are 1.5 inches wider.

This will get the tire centered better in the wheelhouse. It is a little close to the spring with a stock axle. They also has the spring pads in the right place, bolt right in.

Again, I would stay with an 8 inch (or the kinda' rare 9 inch) in a Granada axle. These have the drop-out pumpkin instead of a rear cover.