@Hero,
Yeah, Ford was positive ground until 1956, relatively recent, so to speak.
@Nigel,
Ah, the days when you could start a car with a simple paper clip. At least you could tell whether the generator was working. My Honda died a couple of years ago from a bad alternator. No idiot lights, nothing. First thing that went was the speedometer, then only a few seconds later, the engine stopped cold in rush-hour traffic on a freeway. By "dynamo," is that a magneto ignition or generator in American?