I am taking my car almost completely apart and replacing/upgrading/fixing all the parts. I have been going back and forth on what to do about the rear end. I really want to get a disk brake rear end with posi traction, but I am not sure if its worth it.

At the moment, I have the rear end of a 2.8 L 87 sport coup, but the engine of an 87 350 from a IROC-Z. Could I be losing any performance in the power to the wheels area? Also, I am assuming that the 87 sport coup rear ends did not have posi, is that correct?

I am considering buying a rear end from Hawks (http://www.hawksthirdgenparts.com/in...OD&ProdID=1258) but am not sure it it is worth the money or which one to get. Any suggestions?

Thanks in advance for the input

 

Most likely, you have a 10 bolt non-posi probably like 2 55 gears or something, i had that at least cause i had my rear end out of a 89 iroc auto trans. Basically, i bought the borg warner 9 bolt posi with disks,(the one that came stock on GTA's i believe) and it has 3 27 gears. It was the best money i ever spent on my car. No more embarassing one tire fire! plus it hadles so much better and so much quicker off the line. io highly recommend getting one. I only paid 350 for mine it had 80,xxx miles.

 

Thanks a lot for the information, very helpful. Where did you get yours (probably a junk yard, but thought I would ask)? I would really like to get one, but money is short at the moment. I am down to about $1,200 for paint, headers, and exhaust (hopefully I'll get some more money to spend). Getting one from Hawks will probably cost me a good $600 shipped which will kinda kill my budget.

 

make sure you get the series 3 carrier if you buy a 9 bolt. I got mine from hawks and didnt specify which one I wanted I got the 2:77(my fault). Spent some extra time and money until I found a series 3 carrier.

 

I got a 3.27 posi rear with PBR disks off an '89 GTA for 300 bucks. I was looking for it for over 2 years and ended up driving 120 miles round trip to get it.

I am positive it will be worth it.

To do the drum to disk conversion I need a new prop valve off the MC and since my MC is original I just got a brand new one. I also had to get a new e-brake cable. Don't forget the new speedo gear to make my clock read right going from 2.72 UNLIMITED SLIP to 3.27 limited slip.

I really can't wait for this one much longer.

 

Swap is def. worth it. I went from 2.73 to 3.27, what a difference! If you find one with PBR brakes, you can reuse your old master cylinder, provided you originally had drum brakes, just swap prop. vales. If your new rear has J65 (Delco) brakes, the master is different. Like Caddy said, you'll need new cables.

 

Wait a minute! Wait just one minute!

Did you say you have an 87 V6 rear end? Maybe it's not posi or disk, but I bet it has some decent gears to it. The auto cars usually got 3.42s and the stick cars sometimes got 3.73s!

What you need is a 4th gen Zexel torsen posi unit, used of course!

I'm not a super fan of disk brakes; I think they're over rated. If you really want them, you can swap them onto your axle with some adapters that ebmiller88 sells for a reasonable amount. Just make sure you are getting the good disks. The first ones used on third gens suck worse than drums ever did. I would advise getting these from a 4th gen as well. Even lots of 4th gen V6 cars had disks.

good luck!

 

You could always swap in a 4th gen rear. They are about 2" wider, per side (can get ya discs & a posi...easy to find, parts are easier & cheaper than a 9 bolt) but the extra width is past the control arms. So, they are a direct bolt in.

If you have the OEM 16" rears, you can still use them, and they'll fit under the fenders nicely.

The blue Camaro has a 4th gen rear end, with stock rear 16" wheels...

 

I installed a 4th gen rear also - got posi 3.42 gears for $200 locally from a wrecked LS1 firebird - so I got the nice big rear LS1 disc rear brakes

 

I completely agree. I currently have four third gens and they all have disk brakes and they are all the earlier setup. They are decent at best. My previous third gens had the drums and they felt like they could stop quicker, especially at lower speeds. I suppose there could be something wrong with all of mine though.

 

There is a certain year, 88 or 89 I think, where they switched from the older Delco Moraine disks to the Aussie style PBR units. All I know about them is that they are the ones you want if you are a disk brake guy. I'm not one of them, though...

I have gotten better braking by using larger drums and backing plates from older GM cars in the rear, and that works fine for me.

I like the V6 ratios, all they need is a locker.

 

ditch the spoiler before paint too that thing is ugly!

 

Thats an idea I hadn't considered yet. Does the extra 2'' on each side make a noticeable difference in appearance? It seems like the tires stick out a noticeable amount more than stock, but I can't really tell if thats normal since my car doesn't have the ground effects on it.

Already done. The first thing I did when I parked it was take that off and put on a new hatch with the three piece spoiler and brake light.

Thanks for all the info and suggestions, much appreciated

 

Compare this purple convertible Camaro, with a stock 3rd gen rear axle, to the blue Camaro above.

Not quite the same angle, but it'll give you an idea. The tires won't stick out past the top edge of the lips, it fits quite nice, but exposes a bit more lower, if that makes sense to you.

Our monthly meet is coming up, and I'll try to take pics of 2 cars (one of them with the 4th gen rear) from the same angle on both, to give a side-by-side comparison.

 

I have one of my car from the same angle as the blue one... but it is on my g/fs computer. So once I get over there, I will post it up here

http://www.cardomain.com/member_page...117_6_full.jpg

http://www.cardomain.com/member_page...117_8_full.jpg here are a couple old pics i found on Cardomain (I forgot I had that one...)but that is my 91RS with the stock 3rdgen rear It may not be the same angle, but it will give you an idea

 

Thanks for all the info guys, very useful stuff. I think that I am going to go with a thirdgen rear end because I don't really want the extra 2 inches on each side. I'll be sure to get one with the PBR disks

 

Too bad your not local to me. If you wanted a 9-bolt, I'd trade ya mine for a 4th gen rear end!

Nothing wrong with mine, I just like the wider with look it gives the car! IIRC, the ACTUAL width is 1.75" per side.

 

Sorry to bring this thread back again, but I have another question for you guys. Basically, after crunching some numbers, I found that my budget is going to fall quite short for what I need to do. I really don't want to totally cut out the rear end swap, but I can't afford a $600 one.

So, my question is, would it be worth just getting a posi traction drum brake rear end? They are only $250 + shipping on Hawks which is half the price of the disk brake rear end and in the doable range of my budget.

I am going to check on the rear end from an IROC that is in the junk yard, but I am not sure if it is still there and I don't think it has the PBR disks.

What do you guys think about this? Thanks again

 

Hey man. It seems like you were given a sign the last time you went to that junk yard. That place sounds pretty shady dude.

 

Yeah, I can not believe the stupidity, absolutely astounding. The only reason I will go back is to see how much they want for the rear end I want and knowing that they can't rip me off because I will walk away if I know it is not worth what they want (having done a lot of research on these cars).

 

89-92 with rear discs have the larger rotors (11.7') and single piston alum calipers. Even if the disc rear in question doesn't have PBR's, you can still swap them on:

https://www.thirdgen.org/forums/faq-...iscs-89-a.html

JamesC