I had a 68 bird that had similiar problems. First, I diagnosed the fuel line obstruction possibilities by disconecting the fuel line from the fuel pump, then using compressed air--I gave a shot of air thru the line to the gas tank. That should test if that line is good or bad. Secondly, I installed a temporary electric fuel pump on the inner fender by the right wheel frame and ran a tube from the fuel line (right below your heater box) to the fuel pump, then from fuel pump to the carb. It worked perfect!! I sold the car shortly thereafter so I never got to solve my problem, but the electric fuel pump alteast got the car running. Oh, the electric fuel pump had a positive and negative wire, I connected them to my battery (but used a toggle switch for the positive side to turn on the fuel pump).