6v v 12v Wiring. Is there a load difference?

[waynet]

Folks,

We have taken possession of our recently purchased 1948 M47 Pickup.
The old original wiring is glaring at me and calling fire, fire......
BTW where is the fuse box on these pickups or don't they have one?

Can I replace the old wiring with a new 12v harness and will it handle the 6v amperage? Or should I spend extra coin and convert to a 12v system entirely?

Being a petrol engine we just want safe electrics (nothing fancy).

Much appreciated.