Big Bolt Rears

Right my donor 73 Duster was BBP but manual disc brakes. it's the disc option not the power option that added the BBP.

The other obvious axle swap that guide left out was the Ford 8.8 which seems the best option to me. They cost less, have good ratios, are likely limited slip, can have disc brakes, and are arguably stronger or at least equal to an 8 3/4. Explorer 8.8 puls and extra driver side shaft, cut some out of the passenger side tube and install the new drive side there both centering the pumpkin and shortening the assembly to perfect A body size.