Originally Posted by JSchuricht
The simplest and least expensive way is to slow down.
If you're just after economy, regearing two axles would cost more than the minute amount of fuel you would save over the next 100,000 miles.
Doesn't slowing down take all the fun out of driving?...
The first thing I would do instead of regearing, would be a good intake and exhaust, these help with the overall efficiency of the motor, and I've seen an upwards of 3 mpg better on average.
Not to mention you'll notice how it doesn't feel like you're pushing your truck down the road with the gas pedal, unlike a stock truck where your foot is always buried in the floor board.
Next thing would probably be some good tunes, my dad drives his CCLB at 65mph, with intake and exhaust, and gets around 24-25mpg on a good day, I have friend that drives his CCLB with topper(stock otherwise) @ 70-72mph with a canned superchips tow tune and he's getting 24mpg...
so a good tune does wonders.
If after that you're still feeling the pump bite you in the but, and knowing that the average F150 only gets 15mpg for something half the size of your own, the next step would be a 2 speed overdrive from GV, which adds a second overdrive gear of .60, over the standard .72, but keeping the lower ratio's for towing...