[oldsmo]

hello again,

I found a car and a truck at the local junkyark with 8.5 rears and I was wondering about the bolt up diferences. The car was a 79 buick sedan I think a skylark or a park avanue. And the truck was like a 80 somethin chevy suberban or maybe sumthin a little smaller and was wondering about internal parts, did some of them come with posi traction???. There was no tag on the truck but the was a tag on the car (2KA-B 054 2.41 1)????. And the other questrion is - I heard some of the s-10 8.5 are direct bolt in???????

[Hippie]

'71 through early '89 8.5's had 28 spline axles and later '89 & up had 30 spline otherwise the carriers were internally the same. 2.73 thru 3..73s used one carrier and 2.41 and 2.56 used a different carrier which requires a special gear set or a spacer to install lower gears. Many of them were posi.

Some later 4WD S-10's reportedly used an 8.5 rear axle but it is wider than a 2WD S-10 by a few inches if that's what you're asking.

[Triaged]

GM didn't put any "Posi" (i.e. Limited Slip) diffs in any truck after 73. If it has a G80 RPO code the diff will be a Gov-Lock (Governor operated Locker).

Good luck finding an S10 8.5" if that is what you want...there aren't many out there.

[oldsmo]

is there a problem with the gov-lock in higher horse applications.

[Triaged]

I haven't had any problems behind my mighty 2.8L

Gov-locks have the nickname "gov-bomb" because they like to go KaBoom! The problem is the shock loading when they lock up. From what I have seen it is the case that fails and takes out the R&P and housing (sometimes) with it.

I will be replacing mine with something stronger after I swap in the 383.

[curtis73]

Originally Posted by Triaged

Good luck finding an S10 8.5" if that is what you want...there aren't many out there.

Actually they're pretty easy to find. Any of the ZR2 trucks including the blazer had them; most with disc brakes to boot.

[Triaged]

Originally Posted by curtis73

Actually they're pretty easy to find. Any of the ZR2 trucks including the blazer had them; most with disc brakes to boot.

It depends on what you want. The ZR2 rear axle would be 8" too wide for the back end of my truck and a normal 4wd axle would have been 4" too wide. At that width you might as well get something easier to find out of a full sized car or truck.