460 Gas Mileage Questions

[Muskratt2]

I'm getting ready to rebuild a 460 for my dually. The 460 in my truck currently gets 7 MPG hauling my trailer with race car now! The reason I'm getting ready to rebuild the motor now is because of 2 reasons, 1) the motor in my truck is on it's last leg, 2) I want to try to build my new motor for torque & to get MAXIMUM MPG'S! I know from various 460 forums it's hard to get more than 13-14 mpg's out of these motors. I just bought the book by David Vizard Performance with Economy & have been reading it to try & help me. Have any of you on here rebuilt a 460? How many mpg's are you getting? What all mods did you do to it?