Hy Village_Idiot, that hole should be open to vacuum. That port controls the power valve in the carb, if there is little or no vacuum applied to that port the power valve in the carb will open and allow more fuel into the intake manifold. A friend of mine could not get his 52 Chev to pass emitions, and when we pulled the carb the single hole gasket was not augmented to expose the port to vacuum, once the gasket was installed correctly the car breezed through the emissions test. The gasket manufacturers decided it would not effect the operation if they put four holes or slots in the gasket to make it pardon me "idiot proof", I hope that answers your question.
