[SS Tim]

Its not a matter of "if" it can be done. After all countless IHC pickups like my 75 used a filler tube through the cab leading down to the passenger side tank that ran under the cab and bed. The driver's side (aux tank) has a filler in the front fender.

I am in agreement with SpecialK that this may introduce more problems than it solves. At a minimum I feel it needs a float valve at the tank inlet and beads in the tubes to allow a more positive clamping of the hose joints.