Miles per gallon?

My Slant 6 with a 904 and 2.96 something rear end gears was never in the upper teens early 20's around town either. I averaged 13-14 mpg around town, and got a solid 17 to 18 on the highway at 65-70 mph. It only dropped a half a mile a gallon or so once I had the motor rebuilt and Super Sixed by Doug Dutra, but both sets of mileage numbers were possible only if I stayed out of it pre and post rebuild.

I swapped it out for a fresh 480hp EFI'd 408" 5.9 Magnum with a 4 speed overdrive automatic with lock-up torque converter and 3.91's in it now. It gets the same mileage now, if not better than it ever has. I'll do some more thorough longer distance mileage calculating this upcoming driving season. Same situation though, only if I stay mostly out of it.