I have a orginal 69 SS. A pervious owner has converted the dual fuel system to a single unit (replaced the sending unit, abandoned the return line). When I open my gas cap, I am flooded with gas fumes from the pressure in the tank. Especially after I have driven it for a while. I checked at the part store and no one makes a vented cap for a 69 gas tank. Anyone else had this problem? How did you fix it? I thought about putting a whole in the cap, but then gas might flow out of it. You all know how high gas prices are getting.