Differential Identification

Yep-8-3/4.
Here's a guide for ID'ing Chrysler rear ends:

http://www.mopar1.us/875.html

Basically, look on the left front (lower) side to identify if it's a 657, 741, 742, or 489 pumpkin. There should be a tag on one of the pumpkin studs (if still there) giving the gear ratio (e.g. 3.55= 3.55:1) and another designating Sure Grip. Easy way to tell SG is rotate pinion in direction of normal rotation, see if both axles turn the same direction. Easy way to ballpark ratio is put a mark on one axle, rotate pinion. Count number of pinion rotations to one complete revolution of the axle. Good luck