My '36 Chevy "high cab" PU has a one piece filler neck that bolts to an iron casting soldered to the top of the original gas tank. There is a cork gasket between the iron casting and the flared end of the filler tube that I made from cork gasket material and it does not leak at all when I'm filling the tank. Is your tank original Chevy or aftermarket?
I've owned this PU since 1965 and I've made some "stealth" modifications like changing the rear gears from 4.11 to 3.55, substituting a 1980s era Jeep tandem master cylinder for the original, substituting modern tie rod ends for the clunky originals and hiding a voltage regulator inside the generator to improve the electrical system performance. If that's of interest please let me know.
