3rd gen owner

I put a 305 in my V6 camaro, stats to follow. While I'm waiting for spring thaw, I need to get some gears in it. I'd like to find a posi w/373 gears but the scrap yards don't seem to have any 82-92 left. I've heard (but not verified) that other units will work and I'm asking for input... S10, 4th gen, etc ? I'm not building a race car, I just want a weekend fun machine thats got some get up and go ! Thanks !!
Engine stats, bored 040, mild cam, Holley 600 on a Edelbrock Air gap manifold, headers down to side pipes. All I did to tranny was a B&M shift kit, 700R4. My thots were 373 gears, but open to suggestions!

Killerz187

iTrader: (1)

The only other ones that will work are the ones out of 4th gens. They work because they have the same suspension set up as 3rd gens.

I've heard the best to look for are 98-02 SS rear ends, or stick shift V6's IIRC.

1983Chimaera

The 4th gen rear end is a direct bolt in, but requires a different backspacing rim than the third gen because it is 2" wider on both sides. 15" rims will fit the rear discs available on these rear ends. You may also have to change your brake line fittings over as the earlier third gen cars used SAE fittings, then switched to metric in later years. The 4th gen rears all use metric brake line fittings. If your car was rear drum you will also need either a 3rd or 4th gen brake proportioning valve from a 4 wheel disc car, or install an adjustable proportioning valve such as a Wilwood model. You will also have to find a way to adapt your third gen parking brake lines to the 4th gen rear discs (if installed), or adapt the 4th gen ones to your parking brake handle.
Be aware that the term "posi" is a misnomer. They actually are limited slip differentials, NOT positraction. GM has trademarked the name "Posi-Trac" for their limited slips, the same as Ford uses the name "Trac-Lock" for theirs. Neither is a positraction "locked" differential. Power is supplied to both rear wheels at all times, but the limited slip allows each wheel to spin at different speeds for cornering. A true positraction will supply power to both rear wheels equally regardless of turns, making it highly dangerous for cornering (but fantastic for drag racing). The easiest way to tell if a car has a limited slip is to raise the rear end and put the transmission in neutral, then block one wheel or have someone hold one, while turning the other wheel. If the other wheel doesn't try to turn, it is most likely a limited slip. If the other wheel tries to turn the other direction, it is an open differential (one-wheel wonder). No 4th gen cars were sold with true positraction units.
I have a 1995 Z/28 rear end in my 1983 Z/28, with 3.23 gearing, rear discs, and GM Posi-Trac (limited slip). I used a 3rd gen Firebird 4 wheel disc car's proportioning valve, adapted the 4th gen parking brake cables to attach to my 3rd gen handle, and changed my brake line fittings to metric. I'm using the 4th gen Z/28 16" alloy rims for fitment, with 2.5" aluminum adapters on the front spindles to adapt for the backspacing difference. Everything else was a direct bolt in.

JamesC

iTrader: (5)

Welcome to TGO. Here's some general info that may prove useful:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

big gear head

If you want a complete bolt in rear end then you are limited to the 3rd and 4th gen F body rear ends. No other rear ends will work. If you are looking to swap the internal parts then the parts from another 7.5 10 bolt will fit, as long as you get the right combination of differential, gears and axle splines. Your '84 will have 26 spline axles. That limits you to '89 and older differentials. If you get 3.73 gears from a S truck then you will have to use a 3 series differential. All of the S trucks with the limited slip differential got the Governor Lock. This is not recommended for a performance car. If you find a used Auburn from a 3rd gen then it's probably going to be worn out, or close to it. These can not be rebuilt, so I do not recommedn using one of these. You would be better off getting a new Duragrip or Eaton Posi.

3rd gen owner

Ok, You guys are getting me heading in the right direction then, thanks. I think I prefer to try and stay with a 3rd gen rear end instead of the extra effort involved in doing a 4th gen. And I was seeing info on S truck swaps, but not too sure on that either. Any more info out there from all you camaro buffs ?? Thanks, Guy

3rd gen owner

Oh, and do you have info on the best place to get the Dura or Eaton ?

Killerz187

iTrader: (1)

There's only a marginal amount of extra effort to swap in a 4th gen rear, if it was me, I'd swap in the 4th gen while I was taking the rear end out anyway.

S truck swap isn't going to work, not without a s***-ton of custom fabrication, and even then I don't think it'll work.

You could probably get a rear end rebuild kit off Summit, or some other parts distributor I'm sure.

1983Chimaera

I think my 4th gen rear swap on my '83 took me about 6 hours at most. It's really pretty straightforward, even with the brake lines / proportioning valve / parking brake cable issues. They're also appearing with more frequency in the junkyards, and tend to have less mileage on them than comparable 3rd gen units. Bear in mine they also feature vastly upgraded brakes (the rear discs are huge), stronger axles, and an improved limited slip over the older 3rd gen units. 3rd gen wheels will bolt to them, but they will stick out on either side because of the increased overall width of the rear end. This can be solved at least temporarily with 4th gen rims from the junkyard. You sound like you're already planning on going the used parts route as it is, so why not do it right?

JamesC

iTrader: (5)

The 89/90-97 rears have the same 28-spline axles, Auburn limited slips, rotors and PBR calipers. 98+ still have 28-spline axles, but have superior Z/T limited slips and brakes (at least the parking brake).

JamesC

3rd gen owner

Well, I want to stay with 3rd gen parts for simplicity in the swap. I put side pipes on the car thinking it would be simple, but it was quite the ordeal that took a few weeks to finish (work week and other things going on) and lots of fabricating. While I want what I want (LOL), I came to realize that I need to keep it simpler in the process !! Putting in rear disc would be nice but I have an 84 Z (parts car)that may have the 28 spline axles. Reading and educating here tells me that I should stay away from the older used stuff so now I'm thinking just get a new posi (limited slip) unit and gears... So thnks for all the useful input !!!
SOOO, going back to the engine info I gave in my original post, what gears would you guys recommend ?? I just want a weekend fun machine that has get up and go when I put my foot in it. If you recommend gears, I'd like to know why you recommend em... remember,I'm educating here LOL !! Thanx again !