What bolt is our rear end ? What spline axle ? ...Thanx

 

I blieve they are 10 bolt 7.5 ring spline no clue...

 

This axle design was created in the late 60's for application on the VEGA of 1970.
Yes, true.
Same rear design as in the S-10 Series trucks, too.
Then in 1989 they beefed up the rear, completely, where as nothing from previous, internally was the same. But, housing was similar.
That include axle spline counts.
But, it is a fair design for abuse under power.
ie, a six cylinder cannot destroy it nor can a factory V-8, FROM THE FACTORY, not "HOPPED UP".

 

10 bolt ring gear. (Common mistake is using the # of bolts around the cover; the true # is pulled from the # of bolts on the ring gear. It just so happens that the # bolts on the cover equals the # on the ring gear!)

Around 84-85, GM went to a 7.5" ring gear instead of a 7 5/8" ring gear- but for all intensive purposes, they're the "same size". Mid year 1988, GM went from a 26 spline axleshaft to a 28 spline axleshaft. 1987-below will DEFINATELY have the 26 splines, 1989-up DEFINATELY has the 28 splines, and an '88 owner has to pull the diff cover off to check.