Most will probably call you a liar but I consistantly get 15.5-16 unloaded out of my 07 classic 6.0. 65mph seems to be the sweet spot for milleage in these trucks, my 03 performed the same way. I run 285s on both trucks, the 03 had intake, exhaust, & programmer. The 07 just has a bullydog gt.I was able to pull a solid avg of 15 mpg hauling this load up the dunes a couple weekends ago.. backed down to 65mph and wasnt in a hurry .
the front quad catches a lot of wind,