International is no different than any other make as far as gearing goes. First figure out what ring and pinion gear ratio you have and then switch them out to the ratio that fits both your tire size and desired cruising speed/rpm. Your truck has Dana axles which were used in Chevys Fords Mopar Jeeps and a whole bunch of other makes too. Lots of gearing choices and traction aiding options available.
Find your gear ratio:
https://www.youtube.com/watch?v=CqA64CU2w_U
Calculate your new ratio:
http://www.4wheelparts.com/off-road/...-diameter.aspx
Nice Travelall!