Here's what I have in the 1980 D-50 to run 32" tires:
4.88 (4.875) ring and pinion set; was sold by John Baker Performance in 1982; Mitsubishi parts; 39 teeth on ring gear, 8 on pinion. Ring gear is 10-bolt.
Installed straight into 1980 Dodge D-50 rearend. Told it is part number MB 527147. When I tracked down John Baker a decade later he said it was a stock Mitsubishi part, but didn't remember what vehicle.
When it blew due to cracked tooth (long story,) I was number 19 on the waiting list until Mitsu in Japan would set up the CNC to make a run of 20. Had to order a second set to get them to run. Have a spare so it will never happen again!
Told it was only put in something called a "high-altitude version Montero" and is very rare. Now made of Unobtainium ...
Looking in the Wiki it doesn't say anything about them.