JoeBlack would be a great contact for a CUCV with a diesel but this truck does not have a diesel anymore. Nor does it probly have the 24 volt system. Jack, you need to ask yourself some questions... and be honest with yourself. Is this truck going to tow a boat to Chatfield? Is it going to drive/tow to Moab? Is it trail mostly? Can you afford and dedicate to an awesome swap/build and what comes with it? The TH400 has no overdrive and since the axles have 4.56 gears the trucks top out quickly and since the CUCV's lack sound deadening/insulation a reving motor could get extremely annoying.

If I were you I would be on the lookout for a motor trans combo from one truck with computers (maybe even motor trans t-case combo). The NP208 is good and kinda strong but it is not an NP205. Consider also a Stak gearbox. In addition, these trucks are prime candidates for a doubler setup and if you include an OD trans in the swap, you have the gear spread covered.

I would consider an 6.0-LS 4L80E swap over a 350or454 700R4 personally. But I also understand the temptation of a simple 350 motor replacement when everything already works as is. The Holley Truck Avenger carb does a great job offroad and can keep this truck on the more budget-friendly side. Colorado is a hotbed for combos like these and ColoradoK5.com can walk you thru a swap blindfolded. Keep us posted!