Joel
I'll try and explain how it should be done....
Here we start with the Fuel Cell with vents on both sides
Then we weld in the Aero Fuel cap inside of the Quick Fuel on the fender
Now we drill holes in the outside cap for vents on both side of the fuel cell
Now we go to the outside cap and drill two holes above the Aero Fuel cap so the fuel fumes can vent to the outside ambient pressure.
Then we mount Check valves to the vent lines coming up from the fuel cell vents on the corners of the fuel cell.
Now you can see the Check valves attached above the Aero Cap to vent to the atmosphere and from both sides of the cell for high speed corners in either direction.
Also please note the ground wires going from the cap to the chassis of the car so you have no issues with static electricity to ignite any fuel vapors.
Sorry for the long post
Morris