If your intent is to hold 70 mph up hill at altitude I'd recommend avoiding a diesel engine that is smaller than 5.9 liters.
Just do a GM gen IV swap using Nick's parts. You will have the power and the convenience of an auto and the drive ability of a modern GM pickup or SUV. In the end you will have spent only slightly more for the GM swap but will not have a 17-26 year old engine that is barely getting by. You're trying to drive a 30 year old car like a new auto, put a new engine in it.
Do not read the next sentence.
You little rebel, I like you.