Rocketman Tach Conversion - Installation Wiring Question

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1973 Q code Mach 1 blue glow with argent stripes, 351C-4V, C6 auto
1973 Q code Mach 1 blue glow with argent stripes, 351C-4V, 4 speed
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.

 
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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.

 
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Joined
Apr 3, 2011
Messages
551
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Location
United States
My Car
1973 Q code Mach 1 blue glow with argent stripes, 351C-4V, C6 auto
1973 Q code Mach 1 blue glow with argent stripes, 351C-4V, 4 speed
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:

 

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