I had a 50 Plymouth special deluxe 4 door in high school. Cruising at 50 mph I'd get 21-22 mpg. At .70 a gallon (1988) I could cruise for hours for $5. Right now I have a 1949 Chevy 6400 dump truck. Driving it back from S Dakota at 40mph. I think it got about 12mpg. Weighs 7500 lbs empty😏