[Zoomad75]

I hate to say it but moving down to a 305/307 is not going to give you better fuel economy. Sometimes going to a smaller engine in a large truck like this ends up using more fuel than a 350 in the same truck. Why? Due to the lack of power to the larger engine you need to run the smaller engine harder to get up to speed and move around. This ends up flushing more fuel down the drain.

Besides the barn door aerodynamics, the heavy weight are just a pain to really squeeze out every last mpg out of. The ones that get the best mileage are running 6.2 or 6.5L diesels with 700r4 transmissions a highway gearing.