318 Idle issues

I feel for you, 67Dart440GT. I went through similar issues with my 340. Turns out that there were 3 intake and 5 exhaust valves with small leaks due to a poor valve job. Compression testing wasn't precise enough to catch this. When I did a leakdown test, I found the issue.
The one thing in all these posts that strikes me as relevent is the fact that you can close off the choke and the engine will still idle fine. That is the anthesis of what the choke should be doing. It should kill the engine immediately when closed unless there is another source of air to keep the engine running.