I noticed in two of your photos that there appears to be a vacuum port on the manifold that is open to atmosphere. It is kind of hard to tell if that is the case, but if it is, that will be a vacuum leak and cause issues.
For what it is worth, those carbs are very finicky with the idle jets. I had one on my early '72 and it plugged up and would not idle, but would run if you kept your foot in it.