[Ron Sutton]

Originally Posted by Build-It-Break-it

Hey Ron, with the Speedway floater mod lite rear end would it make sense to upgrade to 35 spline axles on the diff. side even tho the drive plate is smaller on the mod lite compared to the grand national.

Would the drive plate on high horse power cars give first on the mod lite at let's say 900hp ?

Ahmad

Good questions. I'll do my best to answer.

a. All common floaters use the same OD & Spline out at the drive plate. Moser, Baer, Curry, Speedway Engineering, etc. are all the same size & spline at the drive plate. This is the same OD & Spline for NASCAR, trans Am, etc.

b. So when you're upsizing the spline in the Diff ... the spline at the drive plate doesn't change.

c. The axle OD is bigger with 35 spline axles. So it is a stronger axle.

d. IMHO the 31 spline is plenty strong for what we do & well above what we do. Again, NASCAR with 900 hp engines, 10" slicks & 3500# ... as well as Trans Am, etc ... run 31 spline axles. IMHO the 35 spline is good move when you're drag racing, with a drag prepared suspension & slicks.

e. The power ... 900 hp or otherwise ... is a factor. But the greater factor is loading ... and that comes from grip. On street tires, I don't see any need for anything above 31 spline.

f. All axles break ... eventually. The floater style rear end is a safety measure to prevent catastrophe from a wheel & axle flange ripping off a car at speed. Plus they're made with better materials & stronger.

g. If you go 35 spline, you can not do that with a Mod Lite. The ID of the opening at the end where the hub rides is not large enough for the larger 35 spline axle. So when we go 35 spline at the diff ... you need to go with Speedway's "Grand National" rear end. It is $100 more & runs bigger bearings in the hubs.

Hope that helps.