you dont want any advance at an idle with the vacuum advance line unhooked. 8 degrees BTDC is the correct setting i believe. if you have a timing light just unhook the vacuum advance line, plug it, and make sure, with that line unhooked, that the timing mark doesnt move when you rev the motor...when you have that hose hooked up the mark should move in a steady matter when you rev the motor...that shows that the mechanical advance is "working"..if its advancing to the right setting im not sure about. you need a distributor tester for that
there are some more things to try
