electric choke needed.

It is possible to add an electric choke to the carb. But, you may not like it so much. A mild mod can be done with the use of a Edelbrock/Carter Electric choke. It will bolt on.Perhaps you may to drill and tap where it gets mounted to on the side of the carb.

Is adding a manual cable out of the question?

Where are you located? I do not know of anyplace called Capac.