Not everyone drives the same. or have the same road conditions. i drive 160 miles a day.just bought a 76 dartlite. i'm testing these theories. owner claimed 30+ mpgs.
Not doing anything to the car 1 st. trip was 28 mpgs at a steady 1900 rpms. i will do a tread soon. all the adjustments tire pressure, size,etc.. to see what i can achieve.
Not all cars are the same either. owned 12 neons, 2 got 36 mpgs others Not so much. same motors. go figure!