Well gotta 89 305 camaro, heard most people tell me that chevy upgraded to 28 spline axles that year, however I have also been told by a few that its 26 and 1990 was the first year that chevy did these changes. Just curious cuz i wanna replace my 3.08s with 3.73s and a limited slip differential, and I dont wanna go through the trouble of actually unbolting the rear end housing etc etc. Any help would be appreciated, thanks guys

 

You're screwed...'89 year. Only way to know for sure is to pull the alxes.

Ed

 

Very few in 89 had 28 spline. Only if it was made very late in the year. There's a good chance yours is only 26 spline.

Starting in 1990 all the axles were 28 spline.

 

Only Rear Axle in 1989 to positivly have the 28 spline Axle shafts was the BW 9-Bolt, others were a hit and a miss until the stocks were used up. Again depends on the axle ratio for that year. Really no way to tell unless you look.

 

Well doesnt that suck?

 

Not really. You could buy both from Jegs and return the one you don't use. That or take out the rear cover and count the splines carefully. I always thought that past 87 they were 28 spline?

 

1989 was the start of the 28 spline axle shafts, prior years 26 splines.

 

There's nothing really wrong with 26 spline axles. I have a 1978 7.5" rear under my last 2 Malibus, both of which went into the 11s, no broken axles. However, I run them on street tires, never slicks.

I doubt the 28s are much stronger than the 26s. Neither will hold up long behind a strong-launching car. Especially not a manual trans.

 

Great idea, whats Jegs return policy?

 

Well, provided you don't install it and use it for a couple of years, you could easily return it for no questions asked. I would buy both a week before the scheduled install and then return would be quick and easy.