[PeteCruz2715]

I bought a 1928 Roadster that had been in storage for a while. The owner was too old to work on the car and so had his "mechanic" friend prep it for sale. I didn't notice at first that the ammeter would discharge when the engine revved. Anyway the battery discharged after a few days so I thought, "well it is just old so a new one is probably in order anyway." As I was replacing the old one I realized the battery had been installed with the negative lead to ground. I thought the car must have been switched to negative ground at some point since the car started and ran. After a few days the new battery was so dead it would not accept a charge. I bought yet another new battery and switched the cables to positive ground and haven't had any problems since. However I was curious as to what other issues may occur due to switching the polarity. After some research I found that the switch in polarity whether from a change in batt cables or a change at the coil will cause the spark to jump from the outboard sparkplug electrode to the inboard electode instead of vice versa. Apparently this leads to a much weaker spark and thus reduced performance. There is a tool you can buy to check the polarity at the distributor. I'd suggest getting one and checking if you are worried about the possibility of a "polarity" issue. Part #17140 - The part goes for roughly $24