I compensate for 10% slower speeedometer/odometer, I said nearly 22MPG, it was 21.5. I average 15 mixed/around town and on the highway I've gotten anywhere from 18 to 21.5, my average is about 19. It's your truck but I know I sure wouldn't go deeper with the gears, ford went way too deep on most of they're rigs and they suck, it's the sole reason I don't drive my explorer any more. If I were keeping my explorer I would swap in 3.73s in a heart beat.

 

I probably won't go deeper in gear, I'll probably end up getting 33s when these tires wear out, which will have the same effect.

And in case you didn't know, I'm building a 408 stroker for the truck with an agressive cam, 1.7 rockers, and higher flow heads. That motor should put out somewhere around 500 ft*lbs of torque, and how do you make use of high torque? You gear high!