1966 Plymouth Valiant /6 & Holley 1945 carb can only get to idle at 1250rpm. How to get a lower idle without dying?

attached:
- cool instructions that came with my 1920 that looked important for the forum
- whatever this is. electronic choke solenoid? came with the carbs.
- the wire (white going to red/black) that goes to the bottom of the ballast resistor (black plug)
- weird exhaust manifold? Did this exhaust manifold come off a car with EGR? I have no idea what that big port is for.

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