rearend swap from 4th gen to 3rd
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Joined: May 2005
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From: Va Beach, VA
Car: 91 Z28
Engine: 305(LB9) 256hp/332tq @ the whls
Transmission: 700-R4
rearend swap from 4th gen to 3rd
I will be installing a 4th gen rearend into my 91 Z28 since mine only has drum brakes and 3.08 gears. The 4th gen came from a 95 V6 with a 5- speed so the gears will be higher, I don't really care about that, its just a plus. I am wondering if the brake lines are the same as far as location is concerned or do I need to get special ones made. The emergency brake cables are something that I don't know will bolt-on without a problem. I do know that i need a porportioning valve and the master cylinder for a 4 disk car. Another good thing is that I will get roughly an inch more on each side since the axle housing is longer to accept wider tires for the 4th gens. Say good-bye to wheel spacers!! Any help would be great. Thanks!!
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Joined: Nov 2004
Posts: 316
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From: North Jersey
Car: 1990 Pontiac Firebird
Engine: 3.1 V6 soon to be gone
Transmission: 700r4 Automatic soon to be a T56
as far as getting a new master cylinder, I would reconsider. Heres what I learned from redraif's site:
Just some food for thought.
When upgrading from a drum rear, it is said the 82-89 rear discs require the J65 (4 wheel disk) master cylinder. Up until '90, GM used (2) master cylinders, including 1LE. - the J65 for disc/disc cars and the J50 for disc/drum AND 1LE. Starting in 1990, GM dropped the J65 MC and strictly used the J50 in ALL F-bodies - disc/disc and disc/drum.
The J65 Master cylinder was designed with a low pedal ratio for reduced free travel and a firmer and higher effort pedal for the high performance buyer. There was a GM bulletin (Bulletin # 84-88; Section 5 (V); Date: March 1984) stating that people hated the feel of the J65 brakes so they made available the J50 Master cylinder as a replacement. So in pre 1990, when GM customers used to come in and complain about their J65 disk/disk brakes...GM would actually swap on the J50 disc/drum master cylinder. (the one that was on my car) In 1990, the J50 became standard equipment for the disc/drum and disk/disk cars.
The J65 Master cylinder was designed with a low pedal ratio for reduced free travel and a firmer and higher effort pedal for the high performance buyer. There was a GM bulletin (Bulletin # 84-88; Section 5 (V); Date: March 1984) stating that people hated the feel of the J65 brakes so they made available the J50 Master cylinder as a replacement. So in pre 1990, when GM customers used to come in and complain about their J65 disk/disk brakes...GM would actually swap on the J50 disc/drum master cylinder. (the one that was on my car) In 1990, the J50 became standard equipment for the disc/drum and disk/disk cars.
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Joined: Feb 2004
Posts: 814
Likes: 1
From: Savannah GA
Car: 1982 Trans Am
Engine: 383 chevy
Transmission: T-5
Axle/Gears: 4th gen 10-bolt, posi, 3.42 ratio
i have an 82 t/a, and i ordered my brake cables for a 91 z28. I know for a fact you can use the j50 MC, and prop valve, and that your cables will bolt up fine. you actually have a true bolt-in. 
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