Confused on wiring. 1964 Barracuda.

You don't need nor should you plan to add resistors. The only resistance in the original cars was the coil ballast and the wiper motor resistor, the heater motor switch, and the regulator for the gauges, which was a pulsing device designed to simulate lower voltage via that lower duty cycle pulse. So they were not really a resistor

The only time you should need to add any in an upgrade is for LED turn signals, or to dim other lighting LEDs such as for the cluster.