rear ends???
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From: San Francisco, California United States
An 89 would have the PBR brakes which look different from your fronts. They are finned and alot wider looking. They stopped putting 9 bolts in cars in 90. After that they went to 10 bolts again. So you can probably find a Borg Warner rear end from 87-90. MAAAAAAAYBE an 86 here and there, the ones that came out late in the year. The 3.45 disc rear is the most rare and you would be hard pressed to find one laying around. 2.77 an 3.27 are fairly common with the 2.77 being the least popular.
Will
Will
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Joined: Aug 2002
Posts: 1,291
From: Teeter-tottering between Brilliance and Insanity
Originally posted by stanghunter211
An 89 would have the PBR brakes which look different from your fronts. They are finned and alot wider looking. They stopped putting 9 bolts in cars in 90. After that they went to 10 bolts again. So you can probably find a Borg Warner rear end from 87-90. MAAAAAAAYBE an 86 here and there, the ones that came out late in the year. The 3.45 disc rear is the most rare and you would be hard pressed to find one laying around. 2.77 an 3.27 are fairly common with the 2.77 being the least popular.
Will
An 89 would have the PBR brakes which look different from your fronts. They are finned and alot wider looking. They stopped putting 9 bolts in cars in 90. After that they went to 10 bolts again. So you can probably find a Borg Warner rear end from 87-90. MAAAAAAAYBE an 86 here and there, the ones that came out late in the year. The 3.45 disc rear is the most rare and you would be hard pressed to find one laying around. 2.77 an 3.27 are fairly common with the 2.77 being the least popular.
Will
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Joined: Jul 2001
Posts: 769
From: San Francisco, California United States
If you are pulling it out of a stock car, check the glovebox and look for the RPO for that gear.
GH3=2.77
GW6=3.27
GM3=3.45
Check the rear end cover too, there should be two tags one for limited slip fluid and the other reads the axle code right on it. But that could have been tampered with. Its anyones guess really, unless you wanna take the cover off and look in there and count the teeth and then spin to find out how many times it actually rotates. Keep in mind while you are doing all this, BW stuff is not easy to come by, as far as replacements go. Gears too, if you ever get unhappy with em, and wanna upgrade, you don't have many options. Its not like a 10 or 12 bolt where you can get anything you want. Not saying they aren't super rearends, just a little on the rare side all around and since they were only in production on 3rd gens for like 4 years, its not wonder they never made any aftermarket parts or that many upgrades/replacements
Will
GH3=2.77
GW6=3.27
GM3=3.45
Check the rear end cover too, there should be two tags one for limited slip fluid and the other reads the axle code right on it. But that could have been tampered with. Its anyones guess really, unless you wanna take the cover off and look in there and count the teeth and then spin to find out how many times it actually rotates. Keep in mind while you are doing all this, BW stuff is not easy to come by, as far as replacements go. Gears too, if you ever get unhappy with em, and wanna upgrade, you don't have many options. Its not like a 10 or 12 bolt where you can get anything you want. Not saying they aren't super rearends, just a little on the rare side all around and since they were only in production on 3rd gens for like 4 years, its not wonder they never made any aftermarket parts or that many upgrades/replacements
Will
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Joined: Jul 2001
Posts: 769
From: San Francisco, California United States
Not necessarily.
The L98 was available from 87-92 so that means that in
87 it was available in the Z28 and IROC
88-90 only the iroc since there was no Z28
91-92 the Z28 since there was no more IROC
The same years apply for Firebirds, though I am not as knowledgeable about their varients
you will not find a 3.45 rear in a L98, they never produced it. It was intended for the LB9 305 TPI cars with a 5-speed manual. Now it will bolt up just fine, but if you find it on a 350 car, its not from the factory. The only rear gears you will find on a 350 BW 9 bolt are 2.77 and 3.27. Cars with the 3.27 ratio usually got more options like dual cats when it was an option back then. That might help you in you're search.
I am stressing finding a 89-90 one becaus they have better brakes. You can get a 87 if you find it, like i did, but the brakes suck and will have to be changed. And if you are swapping from a car, your car, which has drums out back, you will need a new prop valve. Get the one for your year car, but for the brakes that you are gonna use. Make sure it is for you year car to cancel out any install probs
Will
The L98 was available from 87-92 so that means that in
87 it was available in the Z28 and IROC
88-90 only the iroc since there was no Z28
91-92 the Z28 since there was no more IROC
The same years apply for Firebirds, though I am not as knowledgeable about their varients
you will not find a 3.45 rear in a L98, they never produced it. It was intended for the LB9 305 TPI cars with a 5-speed manual. Now it will bolt up just fine, but if you find it on a 350 car, its not from the factory. The only rear gears you will find on a 350 BW 9 bolt are 2.77 and 3.27. Cars with the 3.27 ratio usually got more options like dual cats when it was an option back then. That might help you in you're search.
I am stressing finding a 89-90 one becaus they have better brakes. You can get a 87 if you find it, like i did, but the brakes suck and will have to be changed. And if you are swapping from a car, your car, which has drums out back, you will need a new prop valve. Get the one for your year car, but for the brakes that you are gonna use. Make sure it is for you year car to cancel out any install probs
Will
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