A Runtz resistor for your fuel gauge.
Forget about the radio, you're also changing polarity. Disconnect it
Wiper motor is probably vacuum operated
Horns don't care
Replace horn and starter relays.
Starter doesn't care.
Clock (if you have one) doesn't care.
I used a mid 60s Dart heater blower motor (12v).
Change out headlamps and light bulbs to their 12v equivalent.
Swap your ammeter wires around since you're changing to negative ground. If you are running more than a 50a alternator, bypass the ammeter.
Make sure you're wiring is in good shape or replace it!!