Finally got everything done on the 58 apache and was set for another road test. 55 year 235 engine ,55 belair overdrive transmission, 3.90 rear end, new radials, shocks, brakes, and 29 inch tires on the back. I hit the interstate for Birmingham just west of Atlanta. The trip was cut short because the road got so bad after crossing into Alabama with all the construction. Total trip was 95 miles round trip running 65 and 70 mph flat out the entire trip some hills but no flat land. Took 9.49 gallons to fill the tank back up. I got somewhere around 9.98 miles per gallon. Does this sound about right for the basic info provided. I don't think 18- 20 miles per gallons is being realistic driving at that speed.