There is currently no Vac Advance to the dizzy. I will have to take some close up photos tonight to see if there is a plugged provision for vac advance already. Otherwise having a read up on it, the vac advance can be installed onto most Kadrons, but based on the Kaddie Shack website it is a fairly technical procedure as it not only involves drilling and installing a barb to the outside of the carb, but also plugging up some of the smaller holes internally to suit. Something that would be pretty easy to stuff up. These are the pictures of the carbs that I have available to me right now. Not much good to me but someone on here may recognize the Vac ports?