If your vac advance is connected to ported vacuum (meaning a port with no vacuum to it when the carb is at idle) you won't have any vac advance at idle, but only as the carb opens.
Sounds like a mid throttle lean surge just off the top.
OK, makes sense so far. How would I go about checking for this and/or how do I fix this "lean surge"?
EDIT: I found some information pertaining to the power valves located in the carb that if too low a value or busted may cause a mid throttle surging. I remember reading that you take your highest possible vacuum reading after adjusting your idle mixture and then divide in half to get your PV value.....if so then it would be a 9?? Seems high to me but I am far from an expert!
