I'm looking to buy a 10 bolt for my 88 iroc. Couldn't find anything locally so I'm going to order a used one from hawks. But My question is should I buy a 10 bolt rear from a 82-88 or a 90-92?

 

90-92 if at all possible.

Shoot for a 3.23 or higher ratio and disc brakes. Don't worry about posi, it won't be working anyway; no sense paying extra for something that's just going to go in the trash.

 

Thanks sofa, looks like all they sell is 90-92 posi disc rears.

 

If you're buying an aftermarket, it doesn't really matter. If you're junkyard hunting, the 90-92 will have 28 spline axles (at least it did when it came from the factory) however a 82-89 can be upgraded to 28 spline axles if you use a 28 spline posi. Factory 28 spline axles are not as strong as aftermarket 28 spline axles and anything is better than the earlier 26 spline axles.

Strength wise, they all still use a 7.5/7.625" ring and pinion. 26 or 28 spline axles, the ring and pinion will still fail first.

Consider the cost of an aftermarket 10 bolt. Then consider the extra cost to go right to a 9" or 12 bolt. The extra cost for a much better diff is a great advantage in the future.