My 8 3/4 is out of what?

I thought the A-body 8 3/4 was 52". The axles sound right if there SBP but the housing sounds wrong.

A body bare HOUSINGS are 52 5/8, those rear end charts floating around the net are mostly wrong.

Replicaracer43 is correct. Housings are 52-5/8" wide and the total width of an a-body axle is 56-5/8" wheel flange to wheel flange