Alternator Gauge Reading High With 300 Watt Stereo System Installed---1969 Electrical System

Upgrade the wiring at the bulkhead to the switch as well. I have replaced alllllllllllll the wires in my car now and have a 300 watt amp as well. My car (65 Valiant) runs half way on the ammeter. Gonna buy temp batt and oil gauges Friday, but mine stays where it was before. Idle the headlights dim but not as bad and I'm running the original alternator. No issues with mine. Have the alt. Checked then check it on the car with the stuff running. If your dropping a lot of voltage, go buy a capacitor. That'll save things better.