ok so i was at my salvage yard looking for some gears for my 8.8 rear end and all of the ones i found that had came out of mustangs seemed like the pinion on it was bigger in circumference around the teeth and all but they were still the same length and the ring was the same size along with the same 10 bolt pattern but the splines on the pinion shaft was a little shorted than the ones on my 4:10s i was just wondering if these will still work and is this stuff different because of them being different brands or what

 

I have seen many pinion gears with the outer end of the gear teeth relieved a bit, this is a non-active part of the pinion's teeth so it make no difference.

As to the pinion shaft spline differences, is the shaft shorter, or just the splined portion? In either case it would depend on how much shorter, however I am not aware of any differences other than slight variations because of production batches, etc.

 

like the teeth and the head on the pinion is just rounder/wider its hard to explain and but they are the same length

 

thats called the difference between 3.27s and 4.10s. Stock pinions look like monsters, yet 4.10s and 4.30s look like little babies.

This is a pick for a 9" rear, but same concept.

4.10s:




vs. factory 3.27s

 

Here's a chart showing the various pinion and ring teeth I've run across:



The pinion OD and relief cuts vary as the tooth count varies, the ring backset varies as well...