Just curious guys. Is it possible/not costing too much, or is there is significant difference between non posi and posi rearends???

Thanks guys

WILL

 

yes you can add a posi.

 

Regardless of 9-10- or 12 bolt or whatever????




WILL

 

Is your rear end stock? go to www.slponline.com and search for their posi units..you just put em in, although w/ your 86 you might have to change to 28 spline axles but the unit is $99 so it's a lot better than gettin a whole new rear end. im gettin one soon.

 

You can add posi to any diff, it's just a matter of cost. I see in your other post that you are considering the purchase of a 3.27 disc diff. My understanding is that only 9 bolts (like the one under my 89 Formula 350) had 3.27 gears. 10 bolts came with 3.23 gears. If it is a 9 bolt, the carrier is not as easy to find as one for the 10 bolt. 9bolt.com has parts for these diffs. But the 9 bolt is a much better diff than the 10 bolt and worth the investment IMO.

 

Excellent. I also know that the 9 bolts are stronger. Price is not really an issue as I wanna do a quality job over time, no rushing, i just thought 100 bucks for a disc rear was a deal worth going after....

Will

 

where can i find out the rear that is in my car?

 

Look in your glove box. One of the RPO codes will tell you

 

2.73 is GU2
3.23 is GU5
3.42 is GU6
3.73 is GT4
3.27 is GW6
3.08 is GU4
2.77 is GH3
3.45 is GM3
3.70 is GS4


These are for 86, so they should be the same for your 87!

Hope that helps

Will

 

ive got a 10 bolt right? (heh....i probably could have just checked myself but why not ask) i went under my car a few nights ago and couldn't find the axle code, iroczone.com or something said it's 3 inches from the rear diff cover....i was behind the car, didnt' see it, i was also wearing nice clothes, so i wasn't willing to crawl much, i was only willing to go as far as the towel went


basically i want to know what i have

 

If you have decent gears already you could throw in a powertrax lockright unit for right at $300, easy enough to install yourself avoiding the fairly high install price of a whole posi carrier. Of course if you can get a whole posi rearend for $100 that is certainly a great way to go. I on the other hand couldn't find much with a posi and decent gears, and my 2.73 rear was killing me, so I purchased a 3.42 open rear from a v6 car for like $75 and threw a powertrax in it. Worked out real nice, no problems.

 

My stock rear is drum 2.73. So I am not gonna waste anytime on that. This other rear is disc non posi, not sure what gear ratio yet. I will have to go look at it first. But I think that is how I am gonna go. 100 bucks isnt too bad I think for a disc rear, they seem to be harder and harder to find these days....

Will

 

Even assuming the other rear is a 10-bolt with the same 2.73 pegleg, it'd still be worth $100 for the disc upgrade. You can't even buy the calipers for that, much less rotors, brackets, pads, brake lines, and e-brake cables to make it work.

 

If you go from a drum rear to a disc rear there is more to change than just the rear, (ex. proportioning valve)
Good luck, Dan

 

Even if I had to change the master cyl. whats the big deal? No one likes to do their own work these days?!??! This is one of the best swaps out there. Sure its a little more involving than a bolt here a bolt there, but come one now.

Anyway guys, this turned out to be one hell of a good evening for me. Turns out the the rear end was a 9 bolt POSI I could not believe it. The calipers are half painted this dumb color, but whatever, I can take care of that easily. The rear came out of an 87 iroc with 67K miles ... It just doesn't get better for 100 bucks. Got rotors, calipers, hoses, ebrake cables, half a drive shaft and brackets, seems they didnt bother unbolting it and just cut the driveshaft as well as mounting points. Also got the rear swaybar...... I will take some pics and post them before and after I get it all cleaned up. Its still got paint on it, as opposed to mine which is a solid rust color...

Will