SOMETIMES... you can get lost in the forest/trees thing...
In the last 10 years or so I had 2 motors that just plain wouldn't idle, I am not stupid, but after chasing these things for too long, I figured out what many of you already know.Some combinations NEED a short and quick advance curve(they need more than "stock" initial advance, but no more that 35-38 total at about 3K.
If you set the initial where it will idle OK, it has waaaay too much total, and the opposite is true
i.e. I was using stock type distributors as triggers.The first one(1 452 RB with the old .509 MP purple)just got an old cast iron tach drive DC electronic distrib.
The second was more recent, and I ended up welding up the advance curve slots below the stator plate about 1/8" and it runs like never before.Not saying this is your problem, but I wasted a lot of time and endured dirty looks from my wife as her car wanted to conk out/overheat/or take off at 1500 rpm idle depending on where I tried the timing that day
Luck, Casey

I'm 55 now, no time to waste. Not a week goes by that I don't hear about someone passing on.Let's get out there,smoke some tires,have a beer with a good friend,do what you have always wanted to do.I am pretty sure no one will ever say on their deathbed "gee I'm glad my life was calm and boring"