im still looking to buying a cummins. but i was wondering what year, trans combo, Mileage before not good to buy, was the best to buy. I just need something to pull my 1977 M880 and the chevy 5.3 just doesn't do it very well. I pu this in here instead of the help section because i wanted help from peopl who own a cummins. thanks for the help and insite.