I did one years ago Kevin. I put new bearings, clutches, springs and spider thrust washers in it. The spiders and shaft were good enough to reuse. I reused the Jesus bolt.
It was a bit of a MacGyver with clamps to get the spring plates in, but I did it. It's really quite a simple design.
The second time round for the 67 I just went and bought a new Eaton 3 series posi with the Carbon clutches, which is quite expensive now. Dave's 3 series is certainly a fair price in todays market.
Clint is correct anything from 3.07 to 3.73-whatever you want to install-I like 3:31 or 3:55 myself-I may have a set of original 3:31 gears for sale-I will know later this week as I am cleaning out a storage unit.
Keep on Cruising!
Dave