[rohrt]

Sounds like you forgot to pull the vacuum advance line back off when checking the idle timing.

You really need to get a tach too. I had stalling issues with one car and found I just had the idle set to low. My loud exhaust was throwing me off.

Pull the vacuum line to the can again and plug it.
Take a reading of the idle advance timing for us.
Take another readin with the vacuum can connected. Then we can see how much advance your can is set at.

If you did have it connected when you took the idle reading then we know your connected to manifold souce.

I wouldn't be all that concerned with factory specs. My tempest won't hardly run with the factory spec of 6 deg BTDC initial. I have set for 14-18 and it runs 200% better. Different gas today, carb and unknown part all bets are off IMO.

I saw in one of your post on the first page that you said you took the air cleaner off and the idle was much better? And I see you just mentioned moving it a bit and changing the idle.

Is the flapper stuck closed in the snorkle? Possible vacuum leak in the line to the diaphram on the snorkle? Maybe try flipping the lid upside down and running it old school as a test I'm not expert but I think it should point to the driver side like you shown in post 13. From factory there was a metal line that ran from the valve cover to the air cleaner in place of that breather cap that is there now.

I can't for the life of me think why moving the cleaner would change the idle unless the air clean is touching something on the car it shouldn't be.