i finally broke the stock rearend in my 87 camaro so i bought a posi unit, 3.73 gears and 28 spline axles off ebay as a package deal. i started working on it today and got it apart and the axles i bought are about 1-1/2" - 2" longer then the ones that came out. the nearest i can tell is that they are out of a 93 or newer f-body, or possibly a different kind of car, is this correct? if its all out of a 93 or newer, will the rest still work? what axles do i need? i've seen different places that they changed to 28 spline in late 87 or 89, which is it? late 87 seems to be what i've heard the most and i looked at posi units from jegs, it says 26 spline 76-88 is one choice, and the other choice is 28 spline 88-up so i take that to mean they changed in 88. do i need to just go to the junkyard and find an 88-92 camaro and take the axles out of it or is it somehting much more complicated?

 

Sounds like you got fourth gen axles.

28 spline, 3rd gen, 10 bolt axles were available from 90-92. There's a slim chance that an 89 will have them but it depends on the exact build date.

All third gen from 82-89 will have 26 spline axles except for the very few 89's which might have 28's. The 87-89 9 bolt diffs are 28 spline but the axles are not interchangeable to a 10 bolt. It would be like trying to put a 28 spline Ford axle into the 10 bolt.

 

ok thanks, i'll go to the junkyard tomorrow and see what we can find.

 

we went to the junkyard today and finally ended up with the right axles after taking one rearend apart to find out the car was marked wrong. where they wrote the year and stuff on the side of it, it said it was a 90 and there was really no other way of telling for sure, couldn't read the date inside the door, the hood was missing, and it had the ground effects that looked like it could have been a 90 but i had no reason to believe otherwise. so it was a major pain to get it apart and took about an hour, then i finally got it apart and counted the splines and they were 26 splines. so we looked the car over good for any way to identify if it was really a 90 or not and the only thing i noticed was it was carburated which i believe they quit making after 87 ish?? so then we found a 91 firebird and made sure it was a 91, i was able to see the date on the door on it, and it was a lot easier coming apart too, only took about 15 minutes to get the axles out of it. then we got it put back together, and the 3.73's were a noticable improvement from the 2.73's, and of course it's a posi now too i know its still just a 10 bolt but hopefully it will last at least as long as the other one did or longer. i was also wondering, how much faster do you think it will be? it ran 13.60's most of the time with 2.73 gears so i'm thinking it should run 13.20's or so with the 3.73's, what do you think? it definitely feels faster.