Reverse polarity will do funny things to voltage regulators, and the generator won't charge unless you re-polarize it, but there probably won't be any long-term problems if the connection is corrected pretty quickly. Ford and Chrysler Corp. systems were positive ground up until 1957, even some of the 12V systems. In 57, all manufacturers standardized electrical systems at 12V negatve ground. 55 and 56 Nash and Packard systems, and 56 Fords were 12V positive ground!
Jerry
