Ignition system, battery to starter/solenoid

Well I'm old LOL. 73. My first RR was in '70 at NAS Miramar, San Diego. Not long after, I helped fix a friend's 68 RR that had failed/ broken the "welded splice" in the black ammeter wire. I had his harness strung all over the place, cluster out, in the parking lot of his apartment. He wasn't too sure I knew what I was doing, and I wasn't all that sure, either !!!!