Need help installing tachometer

[Doug Larsson]

I purchased after market tach and I was reading the instructions it says to connect the red wire to appropriate harness energized ONLY when ignition key is ON (RUN) position .
I took a pic of my wiring diagram am I to splice into ignition 1 or 2 ?

 

[72RoadrunnerGTX]

Factory tachs, on '71-74 B-bodies, were connected to the ACC circuit, yellow molded three-way connector, dash harness, near radio. As for the aftermarket description, IGN 1 is the correct answer.

 

[Grabinov911]

72 Roadrunner GTX beat me to it by 10 seconds!