Dana 60 gear swap.

[Fraser]

New to the site, I have a '67 4X2 with 4.56 gears and, I think, a Detroit locker (B5). I will take it apart this summer to inspect, however, I understand the dana 60 has 2 or 3 different profiles and higher gears will not bolt in, I have BNIB 4.10 gears, but would prefer 3.54 or higher.
I really would like to keep a limited slip, so can the higher gears be shimmed or otherwise used, or am I going to have to find another diff?

With both rear wheels off the ground I cannot turn the wheel unless I put a really long bar on it, the engine will turn, and the other wheel turns the same direction. I think a "clutch pack" diff would turn a little backward, before the engine would turn?