Yes. It'll work. I didn't know about the manual vent valve in the JD's cap and blew the bottom fitting out of my old 210 gas tank, so I put a snowmobile gas tank on the hood with bungy cords and plumbed it straight to the float bowl until I got another JD tank.
With the diaphram type fuel pumps like the one on my old JD, the mechanism is actually compressing the spring in the pump and the spring pumps the fuel to give you a (relatively) constant pressure. Gravity feed should give you more than enough to fuel the tractor.
HTH
Don
Stuck in the seventies- not in the swamp.
(6) Attex, a Hustler, a Super Swamp Fox, (2) Tricarts, (3) Tri-sports, a Sno-co trike, 3 Dunecycles, and a Starcraft! ...so far