72 360 first start question

BTW, are you backing down the ignition timing to try to get the idle down? I am not sure I am reading your posts right.

And do you have the vacuum advance hose on the distributor disconnected and plugged? I would be doing that to be sure any timing variations from the vacuum advance are being taken out.

How does the timing change when it wants to die? And at what RPM does it idle OK?