The cam angle is the number of degrees the distributor cam rotates with the breaker points closed, and is directly related to the breaker point gap. Too small a cam angle provides insufficient time for current through the ignition coil, resulting in a weaker spark. Too large a cam angle means the breaker points do not open far enough and may stick together, causing misfiring. The best way to adjust breaker points is with a dwell meter.

1. The Cam angle, or dwell angle is the number of degrees through which the
distributor cam rotates while the breaker points are closed. It is directly related to
the breaker point gap. Decreasing the breaker point gap will increase the cam
angle. If the cam angle is too small, the current will have insufficient time to pass
though the primary winding of the ignition coil, and a weaker spark will result. If
the cam angle is too great, the breaker points will not open far enough, they will
tend to stick together, and misfiring will result. The best method of adjusting
breaker points is by means of a dwell meter."