Remembered why I got a F450 with 4.30 gears ... observation.

Kayteg1 wrote:
So the only big factor for over 30 percent different mpg was gearing.

Obviously, there's no way 30% was the gearing factor at anywhere close to reasonable highway speeds. Almost everything about the F450 other than the body and bed was different and heavier.

At the end of the day, that doesn't matter though. If you want to optimize for unloaded driving and mpg, go for it. That's not a reasonable tradeoff for many of us who would rather optimize for the loaded case with power going over mountains.