First, I want to say I hope everyone has a Merry Christmas, and thank everyone for the help you have given me so far. I am a novice regarding many aspects of car repair, and bought a mostly restored FB, hoping to have to do little initially to get her running. Now, I have about 5 days I can work on my Bird before I have to park her for about 6 months (if she isn't running). I go to USAF Weapons School starting in January, and the 14-16hr days 6 to 7 days a week does not mix with trying to learn about and then fix my Firebird. To complicate matters, I go out of state for a week beginning Sunday of this week.
The setup- My FB has an electronic fuel pump on the right rear frame rail area. The fuel pump is the smaller square type that clicks, if that helps. There are two steel fuel lines running from the factory tank. One goes through the fuel pump, the other is smaller and does not, and is a vapor return. They both run up to the firewall, where the primary fuel line juts away from my long headers along the right side of the engine compartment, then over to the Quadrajet carb. Engine and carb are likely from an 82 Chevy. The second fuel line runs to the firewall, and was originally capped with a small steel cap with red paint. The carb has a fuel line running to one of the headers, which may be a second vapor return. My tank has a very slow (never really drips, but dried fuel often shows up on the driver side front gas tank corner. The gas gauge currently does not work, but has inexplicably moved once to full and then back to empty after a fillup.
The problem- I went to the gas station for a fillup. The tank was nearly dry, as idiot me wanted to wait until I got back on base to fill up. After filling up, my car began to leak fuel from the vapor return line. The steel red cap had popped off at some point. (Maybe because of the pressure of the fillup?) I put a rubber line cap on the end of it. The next day, when I tried starting the car, it would not start. I popped the hood, and my engine was covered in gas, as the carb overflowed. I think the vapor return cap caused this. The vapor return is a good 18 inches below the fuel tank. I put a 2-foot rubber fuel line on it and anchored it high in the engine compartment, with a filter on the end of it to keep junk out. The leaky carb stopped, and the fuel no longer leaked.
THEN, I drove it about a mile and a half to test it out. When I got home, gas had aspirated out of the air filter, and poured onto the headers. (good grief...no fire though, thankfully)
Question- How do I stop the fuel leak? What should I do with the vapor return line? Should I connect it to the vapor return on the carb? Should I drain/drop the fuel tank and clean out the vapor return? Should I remove the vapor return line completely? (It appears that there was no vapor return line on the 68 according to the '68 Pontiac Shop Manual.)
The second fuel line runs to the firewall, and was originally capped with a small steel cap with red paint. The carb has a fuel line running to one of the headers, which may be a second vapor return. 
