Rearend width

I kind of remember a difference in width between the 71/4 diffs with9 and 10 in drums. Didn't the 10 inch drum face sit out 2 1/2" from the flange the same as the 8 3/4 diff . And the 9" were 2" out.
The numbers I have written down are 56.5 (drum face to face) for the A body 8 3/4 and 58 1/8 for the sbc 7 1/4.
the late Duster 7 1/4 was narrower.