[Lugnutz65]

These pics are from the wiring section of the 1965 FSM supplement. I compared these diagrams to the 1963 FSM and they look the same. All of the V8 wiring diagrams have a black wire (B) going to the middle post on the starter solenoid. Yes, the same post that has the POS+ battery cable. That means the black wire is HOT at all times. The other page shows the black wire (B) terminates on the AMMETER.

I'm trying to help but need to give a disclaimer. I am not an electrical guy so please check this info out with someone else before you fry your instrument panel because I gave bad info.

Here are the pics. from the FSM. The bottom of the page doesn't say C10 but ALL the V8 diagrams show the same wiring for the BLACK (B) wire.