re: 6 volt-12 volt battery question
I used one of these 12 volt batteries with a 6 volt tap in about 1965. I had a 324 Olds in my 40 Ford. I used the 12 volt portion for the starter and electric fuel pump and the 6 volt tap for everything else. What I didn't know at the time was to make sure the 12 volts ran through a resistor so I kept on frying the points. The 12 volt generator seemed to keep everything charged fairly well even with the battery relocated to the trunk. One thing I did use was battery cables made for six volt (heavier wire guage) system. I wouldn't do it now but it worked when I was 19. I drove that car from Regina, Saskatchewan (north of North Dakota) to San Francisco and back in 1966. I just sold it last year.