The danger of a tank behind the seat is in a roll over the cap shears off and spills gas all over where the sparks are being generated by the metal rubbing the pavement. A couple of kids burned to death near here a few years ago in spite of some heroic efforts to get them out. That said, I have one truck with the tank behind the seat and one with the tank mounted under the side of a flatbed. I made it out of a water preassure tank.
