Magnum; in regards to the previous owner it was bought off a lot, so i will really never know. But I doubt the previous owner changed the gearing. Im getting ready to put the 17's back on and try mileage again. Either way, I will be selling a set of tires and rims this spring. THANKS TO ALL FOR ALL THE RESPONSES AND INFO.

 

I just got back from a trip to CA. Drove 75-80 most of the way and got 19.4 MPG. Brought 500# of freight back with me too. I filled the tank each time to overflowing so I know my numbers are pretty acurate. I'm getting 15.5 around town.