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A loop is all you need, but it has to be done right.
The trick is getting the highest point of the loop several inches above the top of the filler. You can do that if you make the loop in the wheel well, at the top of the fender (near the base of the windshield).
Here's the one I put in my car and there have been no escaping fumes since. Ignore the fuel filter I included, which turned out to be completely unnecessary. The fat hose is the line VS installed to bring hot air to the defroster vent. It just served as a convenient mount for the gas tank vent loop.
The only thing that's important here is the height of the top of the loop. No matter how hard you corner, gas won't be driven up that high, so it just drains back into the tank, and liquid gas in the loop serves as a trap, keeping fumes from escaping.
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