Remember the bubbles in the fuel bowl issue on a '56. Well at the Flint show, the car would occasionally stumble when accelerating on the street. When I got home did some more investigating and decided to replace the tank to pump fuel line. When removing the line from the tank sender, noticed that the fitting on the tank sender turned. Long story shortened, the solder on the fitting (new sender installed earlier) was bad and the fitting cracked loose. Resoldered after cleaning up and it was fine and bubbles disappeared. Have not yet done a road test but believe may have found the problem. The fuel pump was pulling air at the fitting thus the bubbles in the filter bowl.