Rocketman Tach Conversion - Installation Wiring Question

[Steve73QMach1]

I recently had Rocketman convert my original style tachometer in my 73 Mach 1. I have a Pertronix ignition. Rocketman's wiring diagram indicates that the switched +12V supply can be tapped off of the OEM tach wiring coming off of the + side of the coil. Isn't that where the resistor wire resides for the OEM style tachs?  The last time I measured voltage there it was around 10.9 volts.  Can I still use this wire for power to the new converted tach or should I run a separate non-resistor wire for switched +12 supply? I'm interested to know how others have wired these converted tachometers.

 

[TheRktmn]

If you use the factory connector/pigtail I send back with the tach to make the jumper you will be tapping into the 12V (B+) ignition wire before the resistor.

Check the voltage under the dash @ the connector - it has full battery voltage.

Put the red tach wire in with the two you combined to make the jumper and you'll be fine.

 

[Steve73QMach1]

Thanks for the quick reply Bob!  Can't wait to get this tach installed as well as the ammeter that I had you convert for me.  Thanks for the service you provide. :tach: