Adding a vapor can

You do know you can buy a roll over valve for the tank vent. Basically it only opens after a certain pressure. If the valve goes upside down (like in a crash and the car rolls over) it closes off the vent, also some models will allow air into the tank but not out of the tank (again in extreme pressure.) They use them for boats, and custom fuel applications. I believe summit sells them. I bought mine from tanks inc.