The Fuel Cell is mounted in the trunk (55 Chevy) on a fabricated frame to allow room underneath, for the drop sump. I can mount filter and pump on the tank support frame, inside the trunk, then run the line through the floor and forward. Or, I can run the tank outlet line through the trunk floor, then to the filter and pump which would be mounted outside (below) the trunk, just in front of the rear bumper. This way, most fittings, and all the pressure line would be completely outside the trunk and driver compartment. This makes the most sense to me as all the line with pressure is completely outside the vehicle - all the way to the regulator mounted on the firewall.
I'm wondering if the regs allow the pump to be mounted outside the vehicle, or must it be in the trunk? There is a firewall where the rear seat used to be.