I have a F350 Dually Long Bed with a 6.7 and use it to carry my Lance 850 Truck Camper which weighs about 2,700lbs. I also pull a light single axle trailer with a 14' boat and get 13mpg doing 65 on the Interstates using cruise control. Without a load of any kind I will get 19mpg on the Eisenhower Interstate system. This is driving in South Georgia and Florida which is flat. Plan to take it out West where the wind always blows 40 knots. Will let you know how it does. MPG since the vehicle was new may be shown on the trip recorder. Bought mine in late summer of 2010. It is super quiet and the exhaust air is cleaner than the air going in the intake! No smut on the tail pipe This was the first year with the new Ford designed engine that uses cow piss (Urea + water) to clean the exhaust. Before that in my 2005 F250 they burned diesel fuel in the exhaust which killed the mpg's Not only that but the pistons made such a racket that you might think they were trying to swap cylinders! I ain't parting with mine! Tight Lines!