in a heavy truck, maybe... but more likely a nv4500 for that purpose.
the ZF requires a 2" body lift & has terrible gearing for a small 4.8 1/2 ton (and weighs twice as much).

but if he never plans to tow much, and especially if it's a 2 door or extended cab (2wd only, though), just grab a T56 from a GTO (the M12 version) and throw some 4.56s in the diff.

at least he's searching, i reckon