I have a 1945 Willys MB and 1954 CJ3B. Both were originally 6 Volt. I was doing a full resto of both (not at the same time) removing the "bubba mod'ed electrical stuff", and needed to replace the wiring harnesses with a Vintage Wiring of Maine harness, as the originals were shot. I converted both to 12 volt, but I got a "looks exactly the same except for the part # stamped on the Autolite dataplate" 12v generator & starter (all bought on ebay advertised as non working, I brought them to my local auto electrical shop and $100 later per set were fully rebuilt with warrantee), got a repro battery that externally LOOKS exactly like a period correct 6 volt, but inside it is a 12 volt Optima battery, and 12 Volt "correct looking" gauges and fuel sender. Other than reading the part #'s on the dataplates on the starter/genny or putting a meter on it, you'd never know it was 12V instead of the 6V it should be. Kill the battery by driving slow in a parade or leave your lights on? Any modern vehicle out there can give you a jump. Not so much if your a 6 volt guy living in a 12 volt world. I carry jumper cables in an ammo crate in the WWII trailer the MB pulls for such an occasion. My M998 HMMWV and M35A2C are 24V and will stay that way. I see no reason to convert them. If someone converts 6 to 12 or 24 to 12 or whatever and does it the right way cosmetically and electrcially, you should have to look REALLY close to figure out it is a different voltage. This is all assuming that you want to do it "period correct".