Ive searched on here but I have not been able to find my answer. I just bought a 90 firebird formula with a disc brake rear. My problem is that I have a tooth chewed off the ring gear. I would like to swap the entire rear out for another so simplify things. What rears are compatible with this one? Am I correct that i can just swap my disc brake components to the new rear? This is my first F-body so i dont know the ins and outs of compatability yet. Thank you for any help possible.

 

Any 82-02 Camaro/Firebird rearend is a direct bolt-on.

The only issues you can run into are the e-brake cables of the LS1rear ends into a 3rd gen & wheel fitment.

Depending on the backspacing of your current wheels, they could possibly stick out. And the disc brakes could be too big to fit, depending on what wheels you have & what year the 4th gen rear end is from. What wheels do you have?

 

They are just the factory 16's. Are all the 3rd and 4th gens just the 7.5" and 7.625"?

 

7.500/625 10-bolt rears are identical with the same internal parts. Only minor difference is the dr.gear OD of.125, otherwise they are the same when ordering replacement parts. Just the same weak rear axle assembly.

 

Yes, as long as the donor rear is disc (a drum rear would require modification to the axle flange or an Ed Miller kit). Your current rear should have the desirable PBR calipers with 11.7" rotors, so keep them.

JamesC

 

Your 90 will have 28 spline axles. Swapping in an 82-89 diff will be downgrading to 26 spline axles. It would be better if you just got some new gears and had them put into your current diff.

 

So a 90 IROC rear with drum brakes has different axle flanges? What a pain. What is an Ed Miller kit?

 

Different from a disc rear, yes. IIRC, the kit allows a bolt-up of disc brake components to a drum rear without flange mods.

http://www.flynbye.com/catalog/i30.html

JamesC