I have a 88 Z28 with the 305 TBI and T5 Trans. I was wondering if i have the 26 or 28 spline axles, my friend told me that they changed it in 88 so i was wondering which mine had.

 

Providing you have a 10 bolt, you have 26 spline. Some people say that the change over was in 1989 but it was only late in the year so only a handfull of 89's may have 28 spline axles. By 1990 all the axles were 28 spline.

You can convert to 28 spline with 1990 - 1992 third gen axles and a 28 spline carrier or with aftermarket 28 spline axles listed for 1990 - 1992 third gens.

 

My friend has a 91 with the axles i can have so im going to try to find a used posi unit and just use his or my axles.

 

Just make sure the posi is for 28 spline axles and you can use your friends axles with no problems.

 

Also make sure the NEW carrier is the correct size for the gears

series 2 = 3.08 and down
series 3 = 3.23 and up to 4.11