I was just looking at the Moser 12 bolt on Spohn's website. What are C-Clip axles, non C-Clip, Full spool? I was looking at this for later on down the road or if I just happen to fall into the money. Thanks for any help on this. For right now I was going to just get some 3.73's an install kit and a posi and throw it into my stock rear, I'm doing this before I do the engine swap. Will my rear last with this setup for a while? I'll be swapping in a 383(not for a while), will the old rear last with that? Thanks guys.

GM axles are held in by c-clips on the end on the axles. They're inside the carrier. If the axle breaks, there's nothing keeping it from coming out the end of the diff (almost).

NHRA rules state that any car running quicker than 10.99 in the 1/4 or has a locked differential (spool) must have an axle retention device.

C-clip eliminators modify the ends of the housing. A retainer is attached to the axles and is bolted onto the modified housing similar to a ford 9". To my knowledge there are no c-clip eliminators for the 7.5" 10 bolt. 8.5 or 12 bolt can have them.

Axle retention device is also rear disk brakes. If an axle breaks, the caliper keeps the axle from coming out of the diff.

A spool is a ring and pinion carrier that has no differential action. The axles are locked together in the carrier. Both wheels turn the same speed even when going around corners. Not a good thing for a street car but used a lot in drag racing.

Wow, thanks a whole bunch. That really clears things up, now I'll know what to look for.