Sounds like a great project. I would think pulling that much weight with 38 inch tires and an overdrive, you might want to consider 4.56 gears. With 4.10's and 38's, you will be under 1500 RPM's at 55.

I have an 05 Ram 2500 with 35's. I towed my M-715 to St. Louis the other day in a heavy wind. Even with the diesel, I wish I had a bit lower gears. I also run under 1500 rpm at 55 mph.

Either way, it sounds like a great project. Can't wait to see your progress. Besides, what better to pull Jeeps with than another Jeep. Good luck.