Rough idle but drives very smooth.

Well I bought all new spark plugs and change them out and the car is running normal.

I do have a slight popping coming out the exhaust and barely noticeable stumble interrupting the otherwise smooth idle.

So now thinking it’s a carb issue, I closed the idle air mixture screw all the way in (Holley 1945) and she increased idle, idles better, and is much more responsive while driving. So now I have the idle air mixture screw fully seated clockwise in.

Not sure what’s happening here.