My 3/4 ton work truck gets 21 mpg unloaded and 19 mpg pulling my trailer.
It also has 555 ft/lb of torque too. Torque rules!
My 69 SWB truck with a decent 350 and 3.73 gears got 13 mpg best ever. I put a built 700R4 overdrive in it and got.......13.5 mpg. That last half mile per gallon cost me 1250 bucks to get!