[Captainfab]

The '60-'62 Chevy C10's typically have the Eaton HO32 differential. There is only one other gear choice other than the 3.90's that are likely in it, and that is 3.38 gears. I believe Yukon gear makes them. But changing gears does not address the 6 lug to 5 lug issue. No one makes conversion axles for those differentials. So you would have to have a machine shop plug and re-drill your existing axles. But there is also the possibility that your axles are worn at the wheel bearing surface.

That '86 8.5" 10 bolt differential is going to be 1.5" wider than your current differential. It will be setup for leaf springs, and a different shock location. To install that differential under your truck, the leaf spring perches and shock mounts will need to be cut off. Then a set of trailing arm mounts and a panhard bar mount will need to be welded on. This needs to be done with careful attention to the correct pinion angle.

An option for you would be to find a '63 to early '70 12 bolt, hopefully with 3.07 gears. The trailing arm mounts will still need to be moved, as the '60-'62 trailing arms are farther apart. The '63 & '64 12 bolt will have the same panhard bar mount as your current differential. The '65-'70 uses a shorter panhard with the mount in a different location, but is easily modified to fit. Now on to the 6 lug to 5 lug issue. There are aftermarket 5 lug conversion axles available for the '63-'70 12 bolts, as well as posi carriers, lockers and many gear ratios.


Either way, this may be a little difficult for you to coordinate from where you are, unless the person doing the work for you is familar with the work involved with changing the differential.