All I'm seeing is a red "X", so your picture host must not be working right. The vacuum needs to come from below the throttle plates, like from a fitting in the manifold, not the carburetor, or a large-diameter fitting at the base of the carb that enters below the throttle plate. If there's a threaded hole with a pipe plug in it somewhere in the manifold, that would be the best location to put a vacuum nipple.
Jerry
