I have a 49 chevy pickup with the gas tank in the cab. The tube that comes out of the bottom for the fuel line is leaking ever so lightly at the base of the tank. Is there some way that I can pull this tank and seal it there. The tank looks in great shape otherwise.

If I have to replace it I want to replace it with a tank under the truck. Can some one tell me where I can purchase a tank for under the truck and where is the best place to locate it.
Thank you