I have an 1986 rear in a 1982 Z. I've been looking at gears, posi's and possibly upgrading the axles to 28 spline. I'd really like to use original 3.73 gears that came in the S-10 and Astros, does anyone know the part number for these? Also, I figured to run an Eaton Posi, is this a good posi? If not what would be recommended.
Lastly, the axles, if I upgraded to 28 spline, what are the best axles? Any assistance is appreciated. Many Thanks.

Using factory parts I would get a 28 spline carrier from a late model 4th gen. Late model thirdgen axles will be needed to fit the diff. If the axles come out of a drum rear and you plan on using discs, you'll need to machine the axle flange diameter down for the rotors to fit. Moser, Strange and Superior all make aftermarket axles. Genuine GM gears are the way to go. They're less likely to whine.

Thanks Dialed, do you know the part number for GM gears or a site I can look into? I've tried some searches and came up empty. Thanks.

You could go to a U-Pull-It bone yard and pull a set from an S-10 for cheap.

The junkyards and ebay are the best places to find good prices on gm gears. I got used 3.73's with a gov-lock carrier from the junkyard for $25, and I also managed to get a NOS brand new set of gm 3.42's off ebay for $50. They're hard to look up at the gm sites because they're always updating and changing the part #'s. When I did get a part# to work, the price was somewhere around $300 for a ring and pinion set!

Pathall, great idea...I'm always leary on the gears though, is there a way to be sure I'm not getting ripped off??

If you're worried about the quality of a used gearset, you probably oughta just buy new. Motive gears are supposed to be really good aftermarket gears. Most guys say they don't tend to whine as bad, if at all, like the Richmonds do. I've seen them for around $150 per set from some of the ebay sellers. Used gears are always a gamble when you're just looking at a picture of them online.