On my 1949 3800 DRW Flatbed, I'm considering moving the fuel tank from behind the seat to under the flatbed between the framerails.

Has anyone done this with an off the shelf (or out of the junkyard) gas tank? Wanting to do it similar to how a newer model flatbed truck would have the filler neck run up under the flatbed down to the tank.

I don't think I want to mess with having a tank built. I know I don't want to try my hand at it. I have a 6400 parts truck with the tank on the outside of the framerail. not sure I want that either.

Mostly, looking to get the tank out from the cab for storage and an increase in capacity.