B body 8 3/4

autoxcuda said
All 8 3/4 rear ends. Info from: http://www.moparts.org/Tech/Archive/axle/17.html

66-72 A-body rear end is 59 1/2" drum to drum

65-67 B-body rear end is 59 1/2" drum to drum... 2 3/8" wider than A-body... 1 3/16" wider on each side

68-70 B-body rear end is 60 1/8" drum to drum... 3" wider than A-body... 1 1/2" wider on each side

A body 8.75's are 57 1/8" drum to drum. I think you got some numbers mashed up there. The B rears are right. There's another link at moparts that does not have that POS chart, i think it's right above the link you posted #16. Has all the correct lengths in it.