The 3.73 with an NV-3500 5 speed transmission would give you truck capabilities commensurate with the rest of a 3/4 or 1 ton vehicle, plus good highway speed. Then all you'll need is an engine with enough torque to pull an overdrive gear like that- - - - -maybe a 400 small block, a 427, or a 454?
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!