That`s a thought Drew.
I was looking at the poly tank from Brothers but I don`t know if I`m too keen on having the tank behind the axle. In the case of a rear end collision I don`t know how that tank would take a hit. It might be easier to have a side mounted tank and easier to graft a filler door in the side. Oh, well I have plenty of time to think about this one. Thanks, everyone for the ideas.
Mike