8 3/4...School Me...

I also found this...sounds like what I have?

Borg Warner Spin Resistant
1969-1974 used the Borg Warner Spin Resistant (# 2881343). This unit utilized a spring-preloaded cone friction arrangement for the locking action. Axle end thrust is taken by the cross shaft. This Sure Grip appeared in '489' assemblies and 70 and later '741'/'742' assemblies. The differential axle bearings are: LM 104912 (Timken cone), and LM 104949 (Timken cup), (Chrysler numbers 2852729 and 2852728). The Borg Warner Spin Resistant unit can be recognized by its lack of bolts on the side opposite the ring gear (like the Dana), and two openings exposing the preload springs. Borg Warner sold this design to Auburn Gear who currently offers the replacement Sure Grip assemblies.