My 250 will get in the range of 18 to 19 mpg at 55 mph, jump up to 70 or 75 and it drops to 14 or less. With a T350, 3.08 gear, and 28" tires, its running pretty low rpm, but low rpm is not always better fuel mileage. You need a lot of low rpm horsepower and torque to pull a low gear. My wifes VW 1.8 liter runs 70 mph at 3200 and gets 30 mpg, so its all in the tune up and design of the whole package not just the rpm. Joe
