What's the absolute maximum range of your Duster?

Today I ran my Duster out of fuel, then completely filled the tank and filler neck with gas. I was able to put 15.1 gallons in. My tank is a new 16 gallon tank. How many gallons does your completely empty Duster take? There must be an air bubble at the top of the tank that prevents the tank from being completely filled. By the way, completely running my tank dry gives me a range of 227 miles, calculated at 70 mph and 14.7 mpg. How far will your Duster go on a tank of gas. I'm surprised at how little range my car has. What do you think?
Back to your original question. The OEM tank is listed as having a 18 gallon capacity. If your tank is 16 gallon it is the wrong one but as long as it fits it really isn't a issue. Just a shorter driving range.