New user with 85GPLE

[Steevz]

Trying to recreate what I had 18 years ago. Pictured is my old 87. Back in the game now, I just picked up a fairly clean and solid 85 with 90,000miles and original paint. Starting to round up parts an make decisions on drivetrain. First up is a set of 1990 16" Formula-Firebird rims, Hotchkis springs, KYB shocks and freshen-up the front end.

Does anybody know if late 80's Firebird gears+posi will fit into a g-body diff ?

 

[Texas82GP]

Love the old GP. Looking forward to seeing the new one! Welcome to the site from Houston.

 

[MrSony]

No they will not fit. F bodies had a series 3 7.5 carrier, and if your gears are below 3.08:1 you have a series 2. You can get 3.08 and steeper gears for a series two, the difference being they are about 1/4 inch thicker, among other things. Try and source a 7.65 out of a Monte SS. That is a series 3. It will have 3.73 in it, so you can go as high as 4.56 and as low as 3.08.

 

[SupremeSpeed]

That's is a nice looking ride! Welcome to the forum.

 

[Texas82GP]

No they will not fit. F bodies had a series 3 7.5 carrier, and if your gears are below 3.08:1 you have a series 2. You can get 3.08 and steeper gears for a series two, the difference being they are about 1/4 inch thicker, among other things. Try and source a 7.65 out of a Monte SS. That is a series 3. It will have 3.73 in it, so you can go as high as 4.56 and as low as 3.08.

I think he was asking if the carrier and gears from the 3rd gen F body will swap over to his housing, which I think it will but am not certain. Hopefully others will chime in. I know it is somewhat popular to grab the Torsen differential out of a fourth gen F body and upgrade the axles to 28 spline, which beefs up the 7.5 about as much as you can.

 

[kalidromos13]

Beautiful Grand Prix!! Man all the grand Prix's here are giving me grand prix envy haha

 

[partsbox]

Steevz, Welcome from Maryland!