Get a 18 gallon keg o' your favorite adult beverage (PBR is pretty cheap), have a couple buddies over to "work on your rod", and once you're done "working" use the keg as your gas tank. It's only a $20 deposit for kegs around here. Have a radiator shop steam and coat your keg (another $30) and there you go... instant gas tank that's cooler than hell.