[Cam1970]

Also check the fuel filter (dirt cheap to replace, tends to clog up if the gas tank is sluggy or gas was not 'pristine'). Not sure if you have carbs, but also check the timing and perhaps adjust the carbs (again, if you have them); if they're
off', the fuel to air mixture could be causing you to waste gas.

And last (but certainly not least, specially if the car is otherwise running well), check the gas tank for even pinhole leaks, as well as any and all fuel lines. I'm speaking from experience here: though my '70 240Z was running rough, the gas mileage was appalling - small pinhole leaks around the 'holding straps' (I'm not an expert with the lingo yet) were dropping a spray of gas when I was driving, which in a way meant that I really didn't smell gas.