Yes, there is a mechanical spark advance that's separate from the vacuum system. It moves the rotor and point cam clockwise to fire the spark sooner according to engine speed, not load. You should be able to grab the rotor and turn it a few degrees clockwise against spring tension, and it will snap back to its original position when released. The parts of the centrifugal advance are located below the breaker plate where the points and condenser are mounted.
Jerry
Thanks for the explanation! I can grab and rotate the distributor easily, and it springs back no problem once let go.
