I just sold a friend an 8 3/4 housing that came from my early A body , but I am under the impression that the housing width is the same on the later A's.
It was narrowed 2 " per side and I had 295-55 X 15 Mickey's in my '65 Dart with a 15 X 10 with 5 /12 " back space. Springs moved to the frame rails and mini tubbed.
That was as big as I could go.
In his '71 Scamp , with the same treatment......3 " inboard springs and mini tubbed ( He used the U.S. Car Tool kit ) , he has 315 - 60 X 15's under it with room to spare , using 15 X 10 Rocket wheels with the 5 " back space.