A Falcon Tank might also work, the filler necks on both the Falcons and Mustangs come out the top of the tank and angle out to the 1/4 panal to the gas cap ( no filler door, on Falcon ), you could shorten the filler and bring the tank farther up in your trunk ( Both the Falcons and Mustangs have no trunk floor, the gas tank is the trunk floor, so you would need to cut the trunk pan out. where the tank would be ).

My '51 should be done this year, paint, interior and tires is all that is left really, other than running a new fuel line.