The weight of the tire/rim combo is not to be over looked. Axles need to be upgraded to deal with the weight and force applied. It will break things if you don't, so please keep that in mind.
Loosing a left front wheel assembly at 60 on the freeway is not a story you want to add to your list. Especially jacked up, when the truck cambers over and digs into the pavement, it is hard to keep the shiny side up.
Idk if he still has any but 100dollarman.com used to bob 2 1/2 tons, so he may have spare axles laying around. Talk to Mark either way, he know his stuff with military tire setups. If your going to do it, do it right.
Maybe even 2 speed axles? Power and mpg.