8.8 Rear-end
 

I am looking to switch from a 7.5 to an 8.8" rear end. What is the difference between 28 spline and 31 spline. Which is better why is it better and is it worth it.

if you have a 7.5 im guessing you have a 6cylinder. (unless its older) the only time your gonna need 31 spline axles is if your putting some decent power to the ground, the 31's are just a stronger axle to handle more power.

sorry didnt read that you had a 94 V6, my fault

Unless your putting down in excess of 340 horsepower daily, you probably won't need the 31 spline axle. I mean its a stronger axle, but with a v6 you probably won't need that much strength anytime soon.

I am setting my V-6 up to drop a 351W into it. Most likly blown.

31 vs 28
 

A 31-spline diff/axle combo is stronger than a 28, obviously, but only worth the extra money if you need it.

If you're dropping in a blown 351 and are swapping out the rear anyway, go with the 31-spline set-up. You'll need it, especially if you run slicks.

Exactly. If those are your plans, definately go for 31 spline axles!

Take care,
-Chris

I'm sorry, but I just do not understand this. Are the 31 splines and the 28 splines the same size diameter? This is the only benefit I can see from this. I mean if they are the same dia. then I can't see the benefit. If you put 31 splines on the same size dia. of the 28's then there will be more splines, but they will not be cut as deep into the axle shaft. On the other hand, you will have more splines to grip with. Theoretically speaking, shallow splines are easier to strip off. The deeper cut splines are easier to snap. So my question is: Is that what drag racers want, to strip the spines rather than to break them? Or is there something that I am just missing here?

More splines = larger diameter = stronger axle.

Take care,
-Chris

Ok, the 31 splines are larger dia. axles. Now I get the point. How much bigger are they. 1/4 inch?

The 28 spline is 1.2" in diameter, and the 31 spline is 1.325" in diameter.

Take care,
-Chris

so bigger is better in this case right PKRWUD


LOL

You betcha!

Take care,
-Chris