[dsraven]

what 4.1l engine are you talking, what years are they made, what bellhousing pattern, what style of engine mounts-side or front, what vehicles did it come in?
again, just my opinion, but if it were me I would install a late model fuel injected engine with an overdrive trans that will achieve good mileage, have easy starts, have a complete front to rear exhaust with catalytic converter so as to not smog out the guy behind you (or you when parked and idling) and be fairly exhaust odor free so others will want to go for a ride with you and not feel they need a shower after to de-odorize themselves, be throaty enough without being so loud you can't carry on a conversation inside the truck. have a rear axle ratio to achieve good power but also decent highway speeds. inside would be comfy seats and a console with a shifter that is nice but not in the way. a/c, tilt, cruise, pdl, p/w, p/seats if you find a deal but not required. well insulated for sound and climate. shoulder style seat belts that work and are mounted to something solid.
in other words, the look of an old truck but the feel and convenience of a modern vehicle. we didn't upgrade for nothing, right?
again, just my opinion. it's your truck so you decide what you like and go from there.