rear disk brakes conversion

[chriscutlass]

hi all i just got a rear end outa my friends 87 trans am(not stock t/a) its a gm 10bolt rear with 3.73.1 gears and disk breaks the thing is im thinking of swapping my whole rear out of my cutlass that has them 2.42. or some crap gears lol to this.
how would i do this and make the rear disk break conversion over from drums to disks? any help is greatly appreciated. and if anyone can tell me what gears came in a stock 87 trans am or cutlass? im new to this car restore so... its a new and challenging thing for me.. i told my parents that before i turn 22 i wana restore a car thats older than i am 😀

 

[FE3X CLONE]

The trans am rear won't work in a G-body. For one, there's no provision for upper control arms since the F-body uses a 3-link rear suspension instead of the G-body converging 4-link.
It's also wider so your wheels would stick out further.

My '87 with 307/TH-2004R had 2.56 rear gears but there were other ratio's available.

 

[chriscutlass]

The trans am rear won't work in a G-body. For one, there's no provision for upper control arms since the F-body uses a 3-link rear suspension instead of the G-body converging 4-link.
It's also wider so your wheels would stick out further.

My '87 with 307/TH-2004R had 2.56 rear gears but there were other ratio's available.

well i kinda see what u mean, but its not a stock rear or gears from the trans am, its a posi rear, he got it out of a another car, i dont no what tho but when i looked at mine and his, it looks like itll line up and bolt in perfectly, all the hardware is the sam ebut like u said its wider and i wouldnt mind havin tires show some, or ill just get smaller tires 🙂

 

[mkiiisupra]

The F-Body rears were actually 7 5/8" instead of 7.5" like the g-bodys. I have heard though that the housings are the same and the internals can be swapped. The axles on the f-body cars are 28 spline as opposed to the 26 spline axles on the g body version which adds a little more strength but not much. You would have to swap everything out of the f body housing into your g body housing if it is indeed possible.

 

[pontiacgp]

some of the 7 5/8 carriers were 28 spline...the 26 spline were more common...

 

[DRIVEN]

Yes, 7.5 and 7.625 parts are interchangeable. I think the only change was the inner pinion bearing change in 1981. I used a posi out of an '87 Camaro in my car's stock housing. It had 26 splines and 2.73 gears. It was necessary to use a ring gear spacer with the 3.42's.

 

[jrm81bu]

some of the 7 5/8 carriers were 28 spline...the 26 spline were more common...

The 28 splines should have come out in 88 or 89, same deal as the s10's.