What would I need to turn my stock 1987 differential into a posi with a higher gear ratio like 3.42? I think I have a 2.73 in there now.

 

A set of gears, and a posi carrier of the correct spines for your axles (26 in your case), and an install kit, and some fluids, and a few hours, and some tools.

 

Whats a good estimate on the cost of the parts in particular the carrier? Do you know of any companies that deal in GM takeoff parts?

Thanks,
Ed

 

The SLP take off posi unit (3-series carrier) is only $99, but you would have upgrade your axles from 26 to 28 spline.

 

Right, if I were doing that for most cars, the SLP take-off is what I'd use. It came from a LS1 car, so it was installed by the factory behind about 360 HP and 375 ft-lbs of torque at the crank, and should be warrantable at that kind of moderate power level.

For other parts, look here. http://www.drivetrainspecialists.com...=28&cat=GM+7.5

 

after that stuff you should have a nice posi rear diff.....

 

my Richmonds 3.73s and the SLP take off posi knocked about 6 tenths off my quarter mile. it is a great unit, especially for the price.

 

I want to do the same thing.. i dont kow my gears cuz comeone ripped off my rpo codes but i simply want to put in a posi... i want cheap but i want posi... can i get one cheap with out changing gears or splines? i have a 88 trans am with 305 TBI LO3

Which leads me to my next question... I'm not sure what kinda trans i have.. (too lazy to go underneath and look up serial number, but when i change my shifter cable i might) I have an automatic but i heard that all trans am's with the v8 came with the 700 R4. i want to believe that but idk anyone who knows this can be of great help
Thanx
Bill

 

more than likely you have 2.73 gears. It would not be a good idea to get a 2-series (for gears lower than 3.23) posi unit for a car with 26 spline axles because if you ever decide to upgrade your gears to 3.23s or higher, you will need to buy a new posi. Just save up some money and do it right the first time. It could be expensive to do it right though, i probably paid about 700 bucks for the parts and labor. I say, if you havent already put money into your exhaust, that is where it should go first.

 

well i always do my own labor.. so i would only need part prices
but id ont believe i will be going as far as changing the gears in my car since i'm happy with it for the most part
thanx for the info