That is the reason for the special offset rear rims. Same offset rear rims on 8 3/4 and Dana rear. Listed in the Scheild book.
If they had Abody width rears, they would have used stock B-body rims off the shelf at much lesser cost and hassle.
Why wouldn't it use the same axles, bearings, gear carrier, and brakes from production vehicles?
Did the S/S Dana uses 10" drums? Wouldn't that have come on a disk brake Dana car? Just had a deep gear set.
An Abody big bolt 8 3/4 housing didn't exist. And they used B-body 8 3/4 off shelf with perches moved in.