Conversion kit. https://www.vintageautogarage.com/1936-1954-Chevrolet-Car-Truck-6v-to- 12v-Kit-foot-p/cc-3754k.htm? gclid=EAIaIQobChMIvIfEhf3Q4QIVFtNkCh3PAwbREAQYASABEgLZMPD_BwE
an alternator change would do it but... make sure everything can handle 12 volts.
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