I don't own a Jeep, but i do own a diesel truck. It's an 86 F250 with a 6.9L International IDI. I'm a little partial to Ford trucks and i don't think you can go wrong with a late model 7.3L. I would seriously consider a later model Super Duty with a Cummins swap as well. They make very nice, powerful trucks with a dead reliable engine that could last a half million miles easy.