My current S/P car has a narrowed Dana 60 with Mark Williams 40 spline axles, two of his steel caps and it had one of his 40 spline aluminum spool with a set of Pro 5.86 gears when I got the car without a motor in it. I was told the rear gear ratio was either a 5:13 or 5:38 ratio, which with 16x33x15 tires should have worked fine with the 511 C.I. 400 E 85 stroker motor I put in it to race it.
I got it running in the summer of 2013 and ran it once at a 1/4 mile track and fund out my stroker motor had its tongue out at 7300 RPM around the 1000 ft timers
I check the gear ratio that winter and ended up finding out it had the 5:86 in it so I swap them out to a set of stock Dana 4:56 as I could not find a 40 spline 3 series 40 spline spool
I wanted to put a set of 4:30 in it but I had to use the 4:56 gears and a Moser 40 spline steel spool as no one back then made a 40 spline 3 series spool
I use two short pry bars to pry on two ring gear bolts to remove the spool and ring gear and installed the 4:56 pinion using a Pro Parts pinion depth checking tool kit
I had to add .003 spacer behind the rear pinion bearing race to get the pinion depth within the specs. on that gear, it has worked fine until the last race of this year when the rear bearing cage failed in the pits allowing all of the bearings to fall out and lock it up
I'm not sure what cause that but I will replace the bearing this winter and make sure none of the teeth on the ring gear and pinion gear are cracked or damaged and reuse that gear set if it checks out okay
Luckily, I was warming it up in the pits and was going less than 2 MPH pulling into tech when the cage failed after I had put it in neutral to stop in tech
I hate Murphy