Dana 60 with upgraded slant six

Old Dakotas IIRC are 7.25s and AFAIK the guts swap over. They are cone-types easily repaired.
I still have one 7.25 SureGrip kicking around too.From a 67 Barracuda 273 as I recall.
Not all old Dakotas were 7-1/4. Most around here were 8&1/4. All the way from 87 and up.