[Ronald G. Stephenson]

Not an issue unless you have accessories like radios and such that are usually negative ground these days. Alternators, at least modern ones, have built-in voltage regulators. On the old systems that used a generator(dynamo), there was an external voltage regulator, and it may have had the means to turn everything off in the charging circuit. The positive wire to the alternator may still be 'hot' when you shut the car off. Easy to check with a volt/ohm meter. This means that it will continue to draw from the battery if it shows 12 volts or more. Just a suggestion. The mossbacks who stand by the 'original' setup will tell you to keep what you have and give up having bright lights and a hot ignition. You may want to hand the car over to a specialist to sort this out. I have two six-volt cars in my stable and will change both over to 12 volts. Yes, they will have alternators.