shadow315

iTrader: (3)

I have read through 100 threads here and I hesitated to even post this as there is already a lot of good info. But, some threads are pretty old and parts availability has changed and so have prices. And, I can't seem to figure out what the best option is for my specific setup..

So... Here's my question. In 2019, what is the cheapest way to get limited slip and 3.42 for my 1992 Firebird while maintaining the stock width?

I have a 350 in the car, probably putting out around 230hp. I have a nice 700r4 in there. I do not want a 4th gen rear. I am not upgrading the motor anytime soon. I only drive the car a few times a month. I am not beating it too badly but I do like to stomp on it from time to time. I currently have an open/2.73 rear end. I believe that since I have the 92, I have 28 spline axles.

I'm not sure if I want to just get a v6 car's rear, or actually upgrade what I've got. I wouldn't mind going to disc brakes while I have it apart but it isn't mandatory. Did any of the V6s have disc brakes? I have read the 82-89 V6s had 3.42, and that the 90-92 V6s had 3.42s. But are the V6 rears LSD?

As a note, I do have the capability of changing the gears out (thanks to a mechanic buddy) if that turns out to be the best option.

Thanks!

84 z28

https://raleigh.craigslist.org/pts/d...982376710.html

sofakingdom

iTrader: (1)

Don't know of any 6-cyl cars that came with either posi or discs. At least, not "standard" options packages; but who knows what all oddballs someone might have ordered. I won't say that "no 6-cyl cars ever came that way". But I wouldn't bet on ever finding one.

If you want "cheap", you're going to have to make some kind of a tradeoff. Either you will have to do a bunch of work; or you'll have to be real patient; or you'll have to settle for a non-disc rear; or something. Nobody in their right mind is going to track down for you and then just gift you a desirable rear axle, all in great shape, all nice parts, etc. Or for that matter, destroy a perfectly good car on your behalf, just to gift you the rear. While "possible", it's just not all that likely. Again, don't bet on it.

Any stock posi in any of these cars is going to be a POS. You don't want it. It'll be an Auburn, and about 99% odds it'll be mostly if not completely worn out. Remember, these cars are all ANTIQUES now. Similarly, you DO NOT want a Gov-Bomb, such as out of a S truck: there is arguably NOTHING more fragile that you could possibly do. You are almost 100% certain that it will break someday, and when it does, it will take out EVERYTHING ELSE in the whole deal. A total loss.

If you can do the gear installation yourself, or as you describe have someone you can trust who's willing to do it for you at a real friendly price, the best thing might be to just buy all-new parts and build it up yourself. Problem being, I would recommend NOT doing this to the rear you have, but rather, getting the best core you can find to do the project to; the core, the thing you'll be rebuilding, is often the cheeeeeeepest part of the whole deal, and there's no sense in sinking a shipload of $$$$ and time and effort into something that isn't the ideal thing to begin with. That means, find a 89-92 disc brake one which can be COMPLETELY worn out or tore up or whatever as long as the housing and brakes are good (which is to say, rebuildable, not necessarily good to go as-is), and build that up. NOT a drum brake one, and above all, NOT a 88-back disc one. From there, I'd recommend a Torsen carrier out of a LS1 car (which can be found used these days), NEW axles, ALL NEW bearings and small parts, and NEW gears. You should be able to come up with all of this for not too much over $750 if you're patient and diligent about scouring all possible sources of used parts patiently until the exact things you want pop up. The core will probably be the thing you'll have to be the most patient about. Don't "settle" for something less just because it's all you can find at the moment; practice some denial of instant gratification, as difficult as that might seem.

shadow315

iTrader: (3)

Thanks, I texted him. It is from a 5.7/auto. I know I can't be sure without opening it but I am guessing it is a 2.77..

shadow315

iTrader: (3)

Oops sorry I should have clarified. Just looking for the cheapest option, not trying to totally cheap out. $750 is fine. I just don't want a $3000 rearend. haha (not in this car anyways).

And yes, I have time to wait for deals to pop up!

Alright, I will look around for a core.

sofakingdom

iTrader: (1)

5.7 / auto might be 2.77 or 3.27 if a 9-bolt, 2.73 or 3.23 if a 10-bolt. Up to 89 it's most likely a 9-bolt; 90-up most likely 10.

You don't really want a 9-bolt. Not because it's not "good" or whatever; rather, because there aren't many aftermarket gears available for it, and what parts there are, tend to be relatively $$$$$. Plus, since the only year of them that has the good brakes is 89, they tend to be scarce, in that configuration; and, if the cones are worn out, as they almost always are, machine work is required. You absolutely do not want one with the 2.77s though; the carrier is 2-series, meaning the highest gear you can put on it, is 3.08. However, if you can find one out of a 89 G92 5-speed car, it'll have 3.45s and the good brakes; an excellent core to refresh, or to just bolt in, if it doesn't need any work. But talk about hen's teeth rare, … .

tater

iTrader: (10)

My 1987 Firebird was originally a V6, therefore it already had 3.42 gears. I found a factory 3 series Posi unit from the classified section here on TGO. Been running it for 8 years without a problem. The swap was extremely easy. Just make sure to keep the carrier shims in the correct place....Lt and RT. They are different thicknesses.