You ready for this?

4.70

Yep, odd as heck I know, 4.70. 47 Ring Gear, 10 Pinion.

another 4.70 would make it easy to get running in 4x4, but I was also thinking of going a step up (or down -- however you want to call it) maybe to a 4.88 or 5.29 so I could put larger tires on the truck.