Vented gas cap?

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This is what I did for mine and then I ran a 5/16 in line back down through the filler neck grommet after looping it up like the metal line in the previous post. I did use some gasoline proof sealer around the fittings. You have to assemble in the car. This was a mock up.

I've forgotten, does the neck flange on the later cars go outside or inside the fender?