noise from distributor/cam gear?

In my expierence the symptom you are describing is usually due to distributor bearing wear or play, even though you came across a cheap used one doesnt mean it works the way it should, why was the person getting rid of it? same reason? it is unlikely that it is not meeting with the cam correctly, it is keyed in such a way that is long as the keys look good and arnt all broken or obviously inop then the problem will lie elsware, if you have a stethascope you can better pin point the location of the noise, or even a piece of tube with a nail in one end and a paper cup on the other will work fine as half ass as it seems. You might try swaping you old and new dizzy back and forth and see if there is any difference in noise level or pitch, also make sure that the last cam cam on that side, the one that is on the outside of the valve cover is properly fit and snug, there are dowels here i belive and if you failed to put them in or lost one ect when you did you valve adjustment this could possibly be a issue, it would not be a bad idea to check the valves either, as if the clearance were off enogh perhaps on the last valve it would cause a slight knock or louder tick (and im not refering to detonation, just the sound created) when it warms up and expands it better meets the rocker arm.