No. These cars do not and should not use a vented cap. All that will do is throw gas all over the side of the car. All these cars are vented by means of a small tube attached near the top of the filler tube in the trunk. Pull that tube loose and make sure it's clear. It simply goes down through the trunk floor gasket, and "open ends" inside the rear frame rail on 67 / newer cars, on older cars not sure where it ends
Shouldn't a car of that era have a simple tank vent? The vent on my'65 is attached to the fill neck near the top. I'd check that for being plugged before doing anything else.
