[Mulletwagon]

For long distance reliability with a 6 volt system the only realistic preparation for an alternator failure would be to carry a spare. I have converted many 12 volt 1950s and early 1960s Fords from generators to alternators and always used late 1960s Ford alternators with external regulators. Don't think too many folks are using external regulators anymore but troubleshooting a failure is pretty easy and the old style regulators (including modern electronic units) and alternators are readily available. My 31 Tudor has a 12 volt one wire alternator and works fine.