1. 3A Pink goes to Positive terminal on HEI
2. 121 White goes to tach terminal on HEI
3. Gauge power, including gas and volt are supplied by 39 Pink. When ready, I will advise this hook up.

(This is all provided you have ignition switch wires and other wires done per instructions.)
Question me if I'm wrong or you need further. If you need help with ignition switch, provide pic of rear of switch and it's markings.

Some of your gauges may or may not end up being mechanical instead of electric. That would be temp and oil. Some have a tube to the sender instead of a wire.
I assume you are abandoning the Ammeter? That's fine. Most harnesses do not support it.


Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn