Nothing has to be changed. I have had a 65 Amp 1 wire alternator on my 56 truck for over 25 years,
both with the 235 and with the V8 conversion. Never had an issue.
It's possible that the reference was for an AD vehicle which was 6 volt.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine