Is this gas cap vented

I had the same issue. I just welded the end shut on the tank. I then got a length of brake line tubing at Napa and I drilled a hole up high in my filler neck. Then weld a nut to the side of the filler neck over the hole you drilled. Take the flared end of the brake line with the flared fitting and thread it into the nut. Bend the tube up high and then back down through the filler neck rubber seal and out to the frame rail under the car.