I did remove the velocity stack and noticed on the #2 carb.'s rubber tube the sealing surface has a portion that has been cut out(missing) around a hole that is not one of the mounting holes. It looks like this could vent to the outside. My guess is this would draw more outside air. Does anyone know if this could cause a "no" vacuum to register on the gauge? Could this be the problem? Also, the others are not perfect, but, have no cuts that lead to the outside.