I've been driving this heap as a daily work truck for about a year. It's 6v and works perfectly. It cranks over as fast as any 12v car. The key is making sure you have 00 (2/0) gauge battery and ground cables along with a properly functioning 6v generator and voltage regulator.
The PowerGen AC generators that are bolt in replacements for the original Delco DC generators were $500 each the last time I looked. They're probably $600 or more now.
Here are two very good companies that make wiring harnesses for antique cars.
YNZ Yesterday's Parts Complete reproduction wiring harness for all makes and models
http://www.ynzyesterdaysparts.com/909-798-1498
Rhode Island Wiring Service, Inc. Wiring harnesses for all years, all makes and models
567 Liberty Lane, PO Box 434
West Kingston, RI 02892
(401) 789-1955
http://www.riwire.com/