What is this!

Looks like a splitter for a mechanical tach/rev. control. The pin sticking out goes into a key hole on a cable end and the other ports also have cables that screw into them. Vintage mechanical tachometers had mechanical rev limiters and one of those was needed to operate it.

Cruise control is primarily vacuum operated but I could be wrong in thinking that part is not used in an old cruise control system. There may very well be a speedometer cable attachment somewhere.