Imagine a car with 400 gallons of fuel and the equivalent type of engine. Basically like a 3 cylinder fuel efficient engine.. (for a car). It was a 9 cylinder wright engine that was used. Shoot, my pickup truck's range with 400 gallons of gas would be 8800 miles (twice the trip that the Spirit of St. Louis could go it had a range of 4200 miles with that 400 gallon tank).
A car that is able to get 36 MPG would be able to more than triple the range of the Spirit of St. Louis with the same gas tank capacity, they would get 14,400 miles in range out of the tank.