I just purchased a disc brake rear out of an 85 z28 I'm planing on putting it in my 90 rs I want to put different gears in it I think it has 3.23 but havenr had the cover off yet I'm looking to find out any info I can and were I can find gears for it I was told they are hard to find don't know if this is true or not any help would b great

 

Wow, use a period sometimes.

Gears are not hard to find. What ratio are you wanting to install? Do you have the tools and knowledge to do the job yourself or are you going to take it to someone to do it? Are you going to use the same differential or are you going to change it too? The first thing you need to do is find out what is in it. You can't do anything else until you know what you have.

 

i think it is 3.23 but could be 3.43 havent had the cover off i would like to put 4.10 gears in it but from what i see the rears were built in austraila and can be a lil harder to get parts for

 

If the rear has 3.23's or 3.42's, it's a 10-bolt. Gears would be plentiful from many sources.

JamesC

 

If it has a rubber plug in the diff cover it is the 9 bolt Australian rear and is probably 3:27 ratio. They can be a little harder to get parts for but they are out there.

 

There are 2 kinds of rear end it could possibly be; a 9-bolt or a 10-bolt.

Count the bolts holding the cover on. If there's 9, it's a 9-bolt. If there's 10, .... you do the math.

AFAIK the 9-bolt wasn't used in 85 Z28s, so most likely, it's a 10-bolt.

For those, gears are EVERYWHERE, and they are DIRT CHEEEEEP. The 9-bolt, not so much.

The 85 disc brakes (82-88 actually) are the ones to avoid.

Personally I wouldn't pay money for that rear, in your situation; wouldn't even accept it as a gift. It's too far from what you REALLY need. You'll come out cheeeeeeeper in the long run to pay more for a core that requires less to be spent on it to make it into what you REALLY want. The CORE is the cheeeeeeeep part; all that stuff you have to buy NEW and do to it, is where the money is.

 

whats the problem with the 82-88 disc brakes

 

They suck

Other than that, not much

The parking brake system is awful, and they don't self-adjust very well, if at all, because of it.

They often are so weak that you can put a car up on jack stands, drop it into gear at idle, and stand on the brakes; and they can't even stop the wheels AT IDLE.

The main thing though is the lack of adjustment thing. Just an altogether BAD design. by getting new ones (they're SUPER CHEEEP - inexpensive besides - so that's not too painful), separately buying the "recall kit" and putting it in them, using the parking brake EVERY SINGLE TIME you get out of the car WITHOUT EXCEPTION and maybe even twice on Sundays just for good measure, and doing the combo valve modification to send them a more appropriate fluid pressure, they can sometimes work almost as well as drums for some people for a short time.

An altogether better option for a T-56 car is to keep your money in your pocket while you look for a 98-2002 10-bolt out of a LS1 T-56 car. You get brakes that are VASTLY superior, a better posi, fewer miles and less age, AND the 3.73 gears that you REALLY need to go with that transmission, all without turning a single bolt.

 

so its the brakes that are the problem not the rear itself

 

The rear itself will have, AT BEST, 3.23 gears; and may have 2.73. It's likely not to have a posi, and even if it does, for it to be completely worn out and ineffective. Which means, you'll have to spend ALOT of money to make it useful with a T-56 and "renew" it.

And, it has 26-spline axles, which limits the carriers you can get for it.

Then, you'll still have an old wore-out rear with crappy brakes, that in the end, drive-in to drive-out, will cost you twice or 3 times as much as just going to the boneyard and getting one like I described with GOOD brakes already on it.

Something it seems near impossible for me, or others with experience, to get across adequately to people who haven't already been burned by bad purchase decisions, is that THE CORE (the old wore-out thing you start out with) is THE SMALLEST PIECE of the cost of a project. The way to minimize your cash outlay is to start out with a core that's already AS CLOSE AS POSSIBLE to what you REALLY want to end up with, because it's cheaper that way.

In fact, assuming you already bought that other thing, you could almost certainly just write it off and throw it in the trash, and go buy the rear I described, and STILL have less money tied up in THE PROJECT AS A WHOLE than putting gears, carriers, brake work, and who knows what all else, into that old thing. And look at the difference in the outcome: a 10 - 15 yr old rear, compared to one with almost 30 years of accumulated entropy.

CL is your friend for finding "the greater fool" to take mistakes off your hands.