Those 6.2/6.5 Detroit's are from a different era of diesel engines. The original 6.2 was designed to be used in the same space as a V8 350 but get much better mileage during the era of oil embargo's (late 70's / early 80's). This is back in the days when a V8/350 got about 180 HP. The 6.2 made about 135 but the mileage was in the mid to upper 20's. The 6.5 is upgraded with a turbo. It made about 200 HP (when the 7.3 made about 220 HP and 500-ish ft-lbs) and I do not remember the torque but a quick search will tell you. There were some that had a lot of problems, especially in the early 90's. I'm betting that '00 model is pretty well the last year or two it was in production. They can be good motors, just don't expect them to be comparable to the 7.3/5.9's of the era. It just depends on what you want to do. On a side note, they were known for their excellent mileage and were the only diesel engine offered in a 1/2 ton pick-up in the 80's/90's until this year EcoDiesel. I also believe they were used in the military HMMV's.