I had never seen the sales brochure or possibly had never really noticed that 6 volt was standard on a 6. I knew 6 volts was offered in the blue chip series because I have one that runs and another parts pickup that also was born with 6 volt. I think what adds to the confusion is that the maintenance manuals only show 12 volts and parts books also seem to allude to everything being 12 volt on the blue chip. I also have a 55 450 series with a 302 that was born 12 volt and a 55 parts pickup that was born with a v 8 and 12 volt. The sales brochure clears up the whole matter.