Welcome to the Zone !!
I assume that this is a 351W engine, please put the truck specifics in your signature as that will help in getting more accurate responses to questions.
The unconnected wire on the carburetor is for the choke, if this is the original carburetor, it is connected to a special 7 volt output on the alternator. If this is a newer carb it is connected to a switched 12 volt source. Also that zip tie doesn't belong there, probably added to hold the choke open.
The device with no vacuum lines on it is a vacuum control valve. This one in particular is for controlling the heat riser function for improved start and run conditions, especially in cold weather.
Not sure what you mean by your distributor being loose, or what you are trying to show in the picture. Do you mean that the rotor is loose or the entire distributor.

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