It is a DTA 360, basically an international 5.9l. It is a lot like a 12v cummins, only wet sleeved (in frame rebuildable) very popular in tractors. International never made a 4x4, they were up fitted with a divorced transfer case and a solid axle front end and mostly sold to the forestry industry back when mine was made. The parts are available, but very expensive. I have been researching Rockwell top loaders and transfer case from a deuce and a half. Far more adorable and parts are easy to get since the 4x4 community uses them quite often. That is my future plan!
Great plan. I guess the trick is making it 4x4 without losing too much street ability. I guess it depends on what type or travel you are looking to do.
Duce parts are abundant.
It seems like the topkick is the easiest 4x4 chassis in that size range to find.
Someday I may look to do something like you. For now my e350 will suffice.