[eagle]

One thing to remember, the Model A is originally POSITIVE ground. If you dropped a battery in, not knowing that, it would definitely create some havoc. As said above, some alternators have been converted to 6V positive ground so looking at the markings isn't really going to tell you much. Most coils will have a polarity marking on them, usually a + on one side of the primary. If the + is going to the distributor then than is an indicator that it is still positive ground. For sure disconnect the alternator until you figure it out. If you bring the alternator to a competent shop they can tell you if it has been converted. By the way, once you figure this out, DOCUMENT it, put a tag on the alternator and somewhere else on the car. This happens SO often, people make "improvements" to the car and leave no documentation for the next guy. Hydraulic break conversions are the worst for this. Also download a wiring diagram, use the search function here on Fordbarn, they have been posted many times. Good Luck!