You guys do raise a good point..and having to throw in a body lift to accommodate the engine would allow me to run 35's w/o too many problems.. that would lower my rpm. but seeing as my 1/2 ton chevy used to do 60 around 1500 rpm.. and that truck hits 2600 rpm to do 60... Not sure if what the mileage would be. lol.. I'm guessin' around 8 mpg's. lol.. anyone have any idea?