Whwn you get it together, put in several gallons. Make sere you have a spare 1 gallon can. When you run out, put in the spare 1 gallon and head for the closest station. When you fill it up, you will know how much gas you have avaible for driving. This is really what's important. Not the tank capacity. You have some at the bottom of the tank you cannot use.
Filler and keep on trucking