Timing Dance ! Vacume Advance ?
Vacuum advance is necessary for ANY engine on the street for cleaner running and better cruising gas mileage. Yes you can just plug it and the car will run fine but your timing will be retarded from optimal when cruising with part throttle (unburned fuel collects in cylinders and goes out the tailpipe because it burns too slowly). Make sure the vacuum line is hooked up to ported vacuum, NOT manifold and when setting the initial/total+mech advance be sure to disconnect the hose.