original Ford switch

Greetings

I am in the process of wiring my coupe using an American Autowire harnness and using Cl***ic instruments with electric speedometer.

I was doing ok until I started wiring the dash. Cl***ic instructions say I should use the acc terminal on the ignition switch. They also say that is the terminal that will come on when the key turned backwards.

The only reasoning I can see is to eliminate interference from some other source such as radio.

Let me explain, I am using the original Ford switch with two terminals. One always hot the other hot when the key is truned to allow the thumb lever to be turned to connect or disconnect the switch. I am using that switch to trigger relays for the panel, and the ignition. I am using a momentary push ****on switch to trigger the Ford starter relay to energize the Chev starter.

I have the speedometer in a dash panel similar to the original and want to maintain the original look.

I have a hot wire directly from the battery through a mega fuse and a remote battery shutoff to a post terminal behind the dash. I could connect a wire direct the that post to dedicated relay to the speedometer. That would be triggered by the ignition switch to power the speedometer, thereby limiting possible interference from some other source through the fuse panel. Or I have enough panel accessory outlets that I could dedicate one through the panel to the speedometer, but their instructions say no, only through the accessory terminal on the later switch.

I would hate to install a late keyed switch to run only the speedometer. Rather go to a mechanical with all its bagage.

Anyone have any suggestions, or what my alternatives might be.

I have emailed Cl***ic for suggestions but they won't get it until next week.

Thank you
Jack Mannen

 

Lemme read back through this when I have a little more time to process. I have rewired both of my '40s, using the stock on/off switch.

 

the relay will work fine. the accessary position is to run things without the ignition, for example listening to the radio without burning the points out.