my '63 sending unit gasket was bad and when I replaced it i used the aviation permatex on the gasket as well as on the screw threads. also the rubber connection on the filler tube needs to be looked at and clamps tightened. if you have dry rot, replace. vapor may not be wet,but sure can stink.

Larry
Old man᠁Old truck᠁neither one goes very fast. All you need in life is TIME, PATIENCE and MONEY.
If you are missing one component, you'll need an abundance of the others two.