Squareback vs round back alternator?
This is a big help.
We see an original starter. The starter solenoid is attached to the starter. From the 1960 diagram, there was no starter relay yet.
Heavy Battery cable to the starter.
At that starter terminal, it is joined with the H-1 wire and A-1 wire.
H-1 is power the horn relay for the horn.
A-1 wire going to the Ammeter's S terminal. This is battery power to everything else. Also is charging wire while driving.