Hmmmmm 1/2 lower with a pressure line from the muffler I think would be better.. seems like your picture showed the tank way too high. is it possible to just unhook the pressure line and try to adjust for gravity???? I like your truck concept but I bet it doesn't corner well??? Like I said in the previous post, up north we used those aluminum sno sledding disks. they worked really good on snow and marginal on grass, but they cornered well.......... Cptn Crash