Matt i use to be into the big tire 4X4 thing myself awhile back and for a good tourqe 350 i would say a good combo for a 4x4 truck would be.
650 cfm carb

cam with about .480-.500 lift (dont go to big on the duration at .50 since its for a 4x4)

good aluminum dual plan intake

smaller tube headers since your after tourqe

upgrade the ignition to something like a MSD 6AL or such

good true dual exuast with quality mufflers like flowmasters or equal

crossover pipe on the exuast would give a few more ft on the torque curve.

Just make sure that the springs on your different heads will handle a bigger cam and that the piston to valve clerance is gonna be ok.

i'm sure others will have different combos but thats the type of combo i have had on a couple of 4x4 blazers that i use to four wheel with and they ran pretty good.