Thanks for the answers. It was probably broken the last time the distributor cap was replaced since some of the pieces are missing. I know some of the pieces are gone because glueing it back together was the first thing I thought of. In going over the engine, there appears to be a number of small items like loose screws, disconnected lines, and miscelaneous screws and small parts left on the intake manifold. Could be attributable to some sloppy prior maintenance.