Hi Dodger,
For my $.02, I suggest you look for a Cummins engine. You'll want the 5.9L, 8.3L, or the (if memory serves) big 10L. The older ones have no computer, are dead simple, and rugged as a granite boulder. You want the inline bosch P injection pump on the smaller 2 and the PT pump on the big one. All 3 can be tailered to your power needs, or wants, easily and fairly cheaply.
Hope this helps a little.
