Okay your gas tank should have a single vent nipple protruding out of the passenger side of the tank. This is what the vent assembly connects too. In the trunk, on the passenger side truck extension, just behind the fender well, should be a hole. The long curved portion of the tube extends up along the outside of the center seam of the fender well. The two tubes of this curved piece then pass through the seal which sits on top of the fender extension. If you look at your passenger side frame rail, opposite the vent tube in the gas tank, you will see a rectangular hole. Both tubes go inside this hole. The longer portion goes all the way through and connects with flexible gas line to the vent tube on the gas tank. The shorter tube exits inside the frame rail where any gas vapors condense/vent. Remember this was back in the days before smog control. I've attached several pics of my car. The hole in the extension is not the stock shape as we used new extensions and cut the hole ourselves. Also, the vent tube assembly is just sitting in position as I haven't purchased a new one yet and just set my old one in position so you could see how it goes. Hope this helps. Let me know if you have any other questions.
