Rear diff swap for 60

[MASTERBrian]

I want to start looking, but curious what to keep eyes out for.

1960 suburban, so I have the trailing arm and coil I'll have to add mounts for. The other thing I'm guessing matter is I'm wanting to stay 6 lug and I have 15" rims.

What I've determined is chevy 12 bolt or Ford 9" is preferable. Regarding the chevy 12 bolt, the 4x4's are the way to go for 6 lug, but I believe the internals are different than the cars....does that matter for rebuilding, etc? What about width, does that change from truck to car? I've read in the 80's I think some trucks had rear disc, I'm guessing that can be issue for my 15's...I did cpp front discs and I have paper thin clearance between wheel and caliper/spindle.

I have a sbc350 putting out about 330hp coupled to a t350 trans. I'm not racing, just cruising around town. I currently have an original 3.90 posi and it's fun, thinking maybe a 3.73 posi is what I'd like to end up with. What I've seen is the 12 bolt rear diffs are about $300-1000+. Seems the 10 bolt are less than $100. Ford 9" seems to be about $200. It seems the trick axles are all really low gear and the cars high gear.

What's everyone using and any pointers for my goal? I kind of figured if I could pick one up cheap enough I'd just build it the way I want, but that gets pricy a well. I'm not in huge hurry as I have a spare 62 diff, but told the seals leak and it's not the posi, which is ok I guess. My 60 diff is obviously near impossible to rebuild if it goes south and it's missing several guides for the clutches and it had trama at some point as there is a long, non-factory, weld along the axle tube and I think there's a small leak from it. I'll likely try to patch that with some fuel tank epoxy and maybe if I make no progress and it survives the summer, swap the innards into the spare housing and try to replicate the clutch guides.