Making power out of the 318

I've had a mild 360 in a 71 Dart years ago that I got to the mid 13s with 4.10 gears swapped in from the 3.23 street gears. It routinely knocked down 17-21 MPG running around on the street. Thermoquad, of course. So I've never seen the 318 argument for mileage, when the 360 CAN get decent mileage.