Slant Six mpg's?

Something else to keep in mind is inaccuracy with the speedometer/odometer. Even if the right gear is in the transmission, if the wheel size or tire size is off from EXACTLY what that gear was made for, they will both read incorrectly. I'm averaging 8/12 (city/highway) in my Dart though it is a 318, but at 55 mpg, my speedometer reads 50.