my 71 scamp with just a cam and a 4 bbl on a 318 got 24 mpg w/ 2.76 gear. then i did a lot more and 3.91's and now im down to 11..

1971 Plymouth Duster 340 auto
1937 Plymouth PT50
1969 Dodge Dart Swinger 340 4 speed
2013 Ram laramie 2500 hemi
2008 Harley FLSTSB springer