Fuel tank venting??
We need to know what model year of your car!!!! These were vented with a very effective and simple system up through 69. After 69 and through 71 ish you MAY have had evap controls (CA state) and after 71ish, the evap controls were mandated federally BUT CHANGED along with the fuel filler cap every year or two.
DO NOT under any conditions put this thing in the trunk