@stoshzack - How can I tell if I have a vacuum advance? I believe it was swapped out by prior owner since it came with an extra dizzy. And I added a Pertronix ignition a couple years ago. Just want to triple check my vacuum connections and where I need to cap. Thanks for all the help‘70s are a special year. You have an extra port on the carb base by your idle mixture screw near the valve cover. Yours is open in your first pic. It needs to be capped to prevent loss of vacuum. Instead of capping, the port can be connected to a vacuum advance dizzy. However, your stock dizzy is vacuum retard.