fuel tank vent line

hello all, I'm having problems with my 1970 plymouth duster I cant put fuel into the tank it always overflows out the fill nozel on-to my paint job? I bought a new sending unit and plan to tank the tank off and inspect do i need to intal a vent line or should I be looking for something plugging up my tank not letting the fuel in? Thanks yall have a great day FERGUSON
Author: Ferguson