[drolston]

With ignition switch on, check voltage at the ignition switch side of the coil. If the points are open, it should read battery voltage (-6V ?). With the points closed it should read about -4.5V. Turn the engine over by hand and watch the voltage switch between those two values. Now try it by cranking using the starter. The voltates should drop a little, not a lot, due to the load on the battery caused by the starter. If the voltages drop a lot, double check your grounding with heavy duty cables battery to starter, battery for ground, and ground to engine block. If the grounds are good, suspect the battery. Report back.