I'm a chevy fan myself, but if you want the power and milage, stick with the Diesel people go with the Cummins and chip it and you won't ask for anything better. The Fords are ok but gutless in drive, and transmissions suck all too H. But make sure you CHIP it. You will get better milage and power. A driver drove 5 plus hrs. on a little over a 1/4 tank with the cummins, not loaded and not chipped, so that is great with a 32 gal. tank. Duramax is a good engine and fair power but milage is better then Fords but not as good as Cummins and the Allison trans are nice.