When I bought my 69 Fury it was running ok but hard to start especially when warm. I dug out my tach /dwell meter and vacuum gauge and tried to refresh my memory with all this stuff I hadn't dealt with since the 1970's. Timing light showed 12 degrees btc ,and I thought fine ,dwell good ,Idle speed good vacuum good. I did notice slight surging at cruise especially going up a slight hill but it ran ok. Still hard to start sometimes cold and bad when hot which I thought was the usual heat soak of the carb etc. I saw talk about ported and manifold vacuum debate. Checked my car and the vacuum advance was on the manifold port. Plugged the port and idled without the vacuum advance and the timing light showed 3 degrees btc. Bumped up the initial to 12 and connected my vacuum advance to ported cured my start problems except if really hot. Surging disappeared too.