i have a 92 z28. the rear is crap, so i want to start over. i want to add disc brakes. i am having a very hard time finding a third gen rear here that has posi and disk. so now, im thinking something new.
what do you all suggest? what is the best bang for the buck? i want gears i can race with, but still drive the care on the interstate n stuff. it has a built 700r4 w/ o/d, so it should work well with the right gears. i also want parts from a company that will stand behind thier product.

 

i just put my rear together 3 weeks ago. I bought my gears, axles,and install kit from moser. all top of the line stuff. then i bought an auburn pro-series posi unit, big difference from the normal auburn posi. i also bought a TA performance cover and carrier bearing stud kit. moving to 3.73's really woke the car up and unless your laying down 500 hp they won't break.

 

well i dont think ill be hitting 500hp anytime soon, im gonna have the LT1 as stock for a while. how much did it all set you back? where did you make your purchases?

 

the gears, axles, install kit and wheel studs were $560. i ordered them directly from moser. the rear end cover is $130 and carrier bearing stud kit is $20. the carrier was $425. the cover is from TA performance and carrier from auburn. if your not planning on laying down serious power you don't necesarily need the pro-series unit, the regular one will work fine.

 

u didnt have to but the housing? like, the whole rear? thats what i need, i need everyting

 

I just used my original housing, there was nothing wrong with it. Of course if yours is bent or damaged or something u can't reuse it.

 

i was under the impression i have the crappy 1 that cant b upgraded

 

as long as the housing is good, you can just put new guts in it. unless of course you can find a complete rear for less then it would cost to fix your old one.

 

Nearly any rear can be upgraded. The stock 7.625" 10-bolt that your car has is the same as most of the guys here, including me. I didn't have the cash to pony up to a 12-bolt or 9", and I'm not making enough power now to justify it anyway.

I used Yukon gears and a master overhaul kit from Randy's Ring and Pinion. You can't beat their prices, the service is great, and shipping takes three days tops because they've got warehouses on both coasts. I bought my axels directly from Moser, and my girlde & studs directly from TA Performance (they're Buick guys at heart, but don't hold that against them). Randy's has any type of differential you want. An Auburn posi is abot the cheapest replacement at $350. Randy's website is www.ringpinion.com

The gears were $160, the kit $100, axel bearings & seals were $60, the axels were $250, the girdle was $145, the studs $20, total about $735. I also bought a new yke as the seal surface on mine was shot. They are about $80 from GM. I do all my own installation & gear set up, so the cost for that was nothing. Most shops charge about $250-$400 for the install/setup. I charge $250, because I know my way around these rears and they are fairly simple to set up once you do a few of them. If you've got to pay to have the gears set up don't forget to factor in that cost.

The cheapest bolt in 12-bolt is goign to cost about $2,000 delivered. A bolt-in 9" will be a bit more pricey. Maybe $2,350 delivered. Then factor in new brakes, ect since some stock brake setups won't work (particularly the drums), and the cost really starts to rise. A beefed up 10-bolt is a great street rear, and does fine with limited track use. I wouldn't try to run one on slicks a lot, especially with a stick trans, but for general use in a quick street car it's a fine rear.

 

Well, it's pretty near impossible to change drum brakes to discs by rebuilding the same housing.

The ONLY kind of rear that's a direct bolt-in to these cars, in one from one of these cars. The ones from 4th gen F cars are close; they're about 1-5/8" longer on each side, which makes your wheels stick out and gives the car that silly r¡cer skateboard wheel effect; but if you're buying wheels anyway, or if you can use 4th gen wheels on it, then they'll fit perfect.

You want a core rear with disc brakes from 90-92. That year range will have the PBR brakes and 28-spline axles. You DO NOT want to put a rear with Saginaw brakes (88-back) in your car, you will hate it. You DO NOT want to put a rear with 26-spline axles in, because they are singificantly weaker, and carriers are harder to come up with and more expensive. You need a 90-92 disc brake core to start out with. Those cores aren't easy to come up with, because there never were very many.

So, very hard time or no, the first thing you gotta do, is come up with a 90-92 disc brake core.

If you want something stronger than a 7½" 10-bolt, about your only options are an aftermarket 9" or 12-bolt.

 

so all these parts will upgrade my 2:73 1 wheel weenie wonder to a posi 3:73? if so im excited cuz i have the money! there is this guy in town with a big mouth... i need to beat him, lol!

 

That 7 5/8" yes not 7.5 as most folks like to call it will not be able to handle 500hp for any amount of time. It will blow up. Ring gear and pinion can not be built strong enough no matter what it is made of. Can't build enough meat into it. The room is not there. Don't waist your time if you want it to handle anything close to that. Switch over to a 9" Ford or a 12 Bolt GM or you will find yourself rebuilding that "7.5" many times. It's cheaper in the long run to go the other routes.

 

i shouldnt have that kind of power right now. i have a stock 1995 Lt1 with 40,000 original miles. The only mods to the engine is the removal of most the emissions equipment. i have no motor plans for quite a while, i just want ti to launce better and b somewhat competative on the street. i lve ina small area, so most guys that street race here just have stock mustangs and 'maros. i should do just fine.

 

It won't handle 500 horses for any amount of time? It will blow up? I agree, it will blow up eventually, but saying that it won't handle 500 horses for any period of time is a silly statement. It isn't like the rear is just going to explode the minute you go to take off on street tires. Is the 7.625" 10-bolt a good rear to run in a 500 hp car? Absolutely not. Will the rear end live for a while until you can stick something better in the car, provided that you baby it? Sure. I would never advise that rear for a car with 500 hp, but we live in the real world, and sometimes financial constraints cause us to do things for a breif period that we'd all rather not do at all. You can't just make a blanket statement like "that rear will explode the instant you go to drive the car", because that just isn't the case. Is the rear living on borrowed time? Yes, but plenty of people have raced with parts that just shouldn't live at all for quite a long time. I remember seeing Gary Rhoe's Mustang running an 8.8 Ford when he was well into the 7 second zone, and it was a 4-lug rear at that! He broke it a couple of times, and eventually I think he went to a 9", but for the time being he just couldn't afford it. He was a real guy who worked a real job during the week so he could race on the weekends. I think that's like most of us here.

 

Why does'nt anyone rebuild their LSD's? What does it cost in parts? Can the work be done yourself with an average gearheads tools? If not what would it cost in labor?

 

People do rebuild their factory LSDs. The parts are like $75 for the plates, clutches, and spring(s). Check out Randy's Ring & Pinion at www.ringpinion.com they have all of the small parts for stuff like this in stock and ready to ship. Their prices are unbeatable too.

Most people just upgrade to an Auburn, Eaton, or other aftermarket LSD. The reason is that the design is better than the factory LSD, they handle more power, and are more durable. They also aren't that expensive. A brand new Auburn is about $350 and they last forever.

 

I'm planning on re-doing the 10 bolt in my 91 Z28. Its a G92 rear w/ the 3.23 posi and drum brakes. The rear is completely stock with 130k miles, I suspect it will fail soon. My idea was to get my hands on a 4th gen LS1 rearend and swap the diff and brakes over to my stock 10 bolt. I thought about that after hearing the $99 SLP drop in posi was OEM 4th gen rearend diffs. I'm lucky my rearend is a 91 with the 28 spline axles. I ended up getting one from an '00 SS with low miles for under $100. Has LS1 brakes and posi. I'm gonna take it to a friend to swap the diff (I've never tried and want it done right). Also gonna get a set of 4.xx gears, not sure which ones yes (4.10 or 4.11?) since the car will be T56. Total cost should be under $500 (rebuilt calipers and all) and that should do for now. I know it'll break eventually, but I also know its alot better than what I got on there.

 

You can put all the good parts in/on a 7.5-7 5/8 rear that you want...(GTA Matt spent $1135 on his, not including labor to set up the gears...so your average guy would be spending another $250-350, for a total of around $1400-1500)...if you are putting decent power through it, and launching hard on sticky tires, you WILL have problems. Sure, the axles may not break, but the weakest link on these rears is the spindly stock housing. Even with a girdle, it will still flex, and you'll either wind up with a serious whine or broken parts. I bent one in a basically stock 95Z, with a few bolt ons, and broke another in a stock AUTOMATIC 94Z. Fortunately, the 4.10 Torsen rear in my SS (with a girdle) was sold before it broke...the next guy broke it a month later, in a mostly stock 97Z.
If you have a street only car that isn't going to ever see stickies, throw in gears and a stock posi and be done with it.
Otherwise, buy a 9" or 12 bolt. BTW, you can buy just the housing and axle package from Moser for $985 , use your stock discs (or drums, or salvage yard discs for another $100 or so), and use a rebuilt 9" posi center section (see them all the time at swap meets for like $350...you can find them in salvage yards sometimes for far less) if your budget won't allow an aftermarket one.
I have seen several used Moser assemblies for sale (9" and 12 bolt) for less than $1500, so that's an option too.
I know a lot of guys try to make the stock rears work for cost reasons, but in the long run, you'll be spending more money, esp if you're having to pay someone else to set it up.