1970 Duster gas tank venting

The 71 (and on some 70 vehciles) with the 4 tubes sticking out of the side is just a crappy inferior venting design, and a pain to hook up. Also the canister in the trunk can be unsafe if fumes escape it and get into the trunk. There's a reason they only used those for a year or so.

Your best bet is to return that tank and get a 72+ tank. Superior venting system, much easier to hook up, and very easy to splice into an existing vent line.