[PONTIAC LARRY]

A trip to a Pick-nPull type yard.. get ya a set of 3.73 or 3.42 gears out of a 1500 Chevy Suburban or Pick up (8.5) , a Posi unit out of 71-81 F body (28 spline 8.5) if on a budget.
With more budget a posi from a 90's Impala or Roadmaster (30 spline 8.5) and a new set of 30 spline axles

if budget allows more get all new stuff for a bunch more money

['ol Pinion head]

Originally Posted by PONTIAC LARRY

A trip to a Pick-nPull type yard.. get ya a set of 3.73 or 3.42 gears out of a 1500 Chevy Suburban or Pick up (8.5) , a Posi unit out of 71-81 F body (28 spline 8.5) if on a budget.
With more budget a posi from a 90's Impala or Roadmaster (30 spline 8.5) and a new set of 30 spline axles

if budget allows more get all new stuff for a bunch more money

Pulled many hundred 28 spline 8.5 S spring posi carriers as cores to build with throughout the 90's & early 00's in Pick-N-Pull yards, crusher yards, cheap country yards. No one pulled more of these in DFW metro area. Will relate that 90% of these used S spring carriers needed new clutches. That was the situation up to 10 years ago & many many of those S spring posi's were pulled from much lesser performance vehicles than T/A's & Z28's. Unfortunately, those new clutches were disco'ed from GM, & are now a $200 expense as they are only avail aftermarket from one small supplier. Add that expense in when figuring what it costs to get into a "budget" used 8.5 posi unit.

On the used 8.5 gears from pickups & vans did the same thing in the early '90's doing budget built 8.5 A-body posi rears. Eventually, using those unknown used high mile 8.5 gears will bite you in the butt. Doesn't matter how experienced or how anal one is with their set-ups, been there, not worth my time today. Its one thing if one knows such used truck gears came out of a quiet tight nice core rearend. Have had luck with several sets of used 8.5 3.23's out of B series Buicks, the 3.42's & 3.73's out of 1/2 ton vans & pickups were always a crap shoot.