12v neg ground on stock 51 merc harness

Can and should I run a fuseable link or additional circuit breaker to protect the stock wiring system on my 51 merc? If so, where do I install? Car is now 12V neg ground. Thanks.

 

I'd say no...
When you run higher voltage, your current draw for a specified load decreases.. meaning your wire size can actually be smaller... 6 volt wiring will be oversized on 12 volt and you shouldn't see any problems unless your wiring or insulation is in poor condition.

 

Thanks Lithium1952! Just wanted some confidence I was good to go. I don't really understand the original circuit breaker setup.