[special-K]

The best mileage I ever got from a small block (307) had an RV cam,HEI with light springs/heavy weights,1/94 valve 64cc heads,headers,and a 450 cfm spread bore Holley Performer.I got 13-14 mpg on the hiway when the speed limit was 55 and I drove no more than 65.Once you break 65 you start losing mileage.The idea was with more effecient and hotter spark,increased fuel/air flow,and more power at lower rpms it took less throttle to get the same power at cruising speed.I had more bottom end grunt at low rpms and more go fast zip at full throttle.But,cruisin`on those tiny primaries sipped the fuel.This was on a heavy K/20 with 4.57s and 37" tall tires and a 4spd!I corrected my odo/speedo with the mile markers and know it was accurate math.I imagine a mile or two more could be eeked out of a C/10 with the right rear/tire diameter.Too tall a gear ratio isn`t the best.The best fuel saver with any combo is the right foot.