7-1/4 question

I'm getting confused. If you have another complete BBP rear, why not just swap the complete rear assy? I drill my own axles. I used to be a tool and die maker, and made a drill jig, years ago.
Some upgrade rear swaps are involved, and some are easy. Some are costly and some aren't.
A fairly easy swap, (if you can find a used rear in your area) is a 8 inch Ford, from a early V-8 Mustang/Comet/etc. It is almost a bolt in, and gives you a "dropout" chunk, BBP, strength, and parts availability. Almost as strong as a 8 3/4, for much less money. Must be from V-8 for 5 lugs, 6cyl had 4 lugs. Has same width, spring perch width. Can hook to the driveshaft with a "Hybrid" U-joint, but I like the idea of having the Ford driveshaft "ears" for the u-joint, put on the mopar driveshaft. That way it is easier to replace the u-joint if required, in the future.