What motor and are you talking 4x2 or 4x4? Roughly the 5.4 will get around 12-14 mpg, the V10 about 8-11 mpg, and the Stroker about 16-20 mpg. Friend of mine has a 02 F350 SD Crew Cab long bed 4x4 stroker with the automatic. Took a trip to Louisiana and got 18 mpg. My V10 4x4 Ext Cab F250 Short bed gets 11 mpg going down hill with the wind pushing and that's on a good day
unloaded. Hook on the 24 ft gooseneck with a load and you're looking at around 8 mpg
on the highway!