What is the gas mileage on a ford e350 box truck?

What is the gas mileage on a ford e350 box truck?
Depends on gearing and if it is a gas/diesel motor, I've worked at a Uhaul center in college and the gas(460/6.8 V-10) trucks averaged 7mpg, and diesels(7.3) 8 1/2- 10 miles per gallon.