Pertronix work with factory tach?

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Tucaz520

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1973 Mach1
Hello everyone 

New to to forum and i keep finiding contradicting word on the pertronix system.

Im just getting started on a 351c 2v. I would like to upgrade to electronic ignition and keep everything under the same cap. I do have the factory tach and would like to keep that operational.  

For now the car us just going to be a driver with performance upgrades much further down the road.  

Im thinking the contradicting word is coming from diffrences in pertronix systems and versions. 

Do any of the current sytems work without digging into the dash to keep factory tach?

 
Joined
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Stock 1973 Mustang Convertible with a 351C 2v and C6
Modified 1970 Mach 1 M-Code with a 351C 4v Manual

I use a pertronix I on my 351C 2v. I have stock dizzy, pertronix flamer thrower coil and stock tach. It all works fine. I am not sure that the pertronix 2 or 3 will work with the tach. The 2 and 3 require direct 12v so you have to circumvent the stock resistor wiring.

 
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71 Mach 1, 351c 4v, C6 trans, grabber blue with white interior
In my 71 I'm using the Pertronix II with their Flamethrower coil (1.5 ohm) and everything works fine.

The stock tach is part of the ignition system in addition to the "pink resistance wire". That wire can go to the + connection on coil, as it probably is now. The - coil connection would go to the black wire of the Pertronix module.

If you want to test the connection, ground the - side of the coil, turn the ignition on (not start) and measure voltage on the + side. You should get around 6-7v.

The dizzy Pertronix module needs switched +12v so you will have to wire that in. If you put 12v to the + coil, you can eventually damage the tach due to excess current.

Be also aware that since the stock tach is part of the ignition, if it goes bad, then your ignition will not work. In that case, can either bypass the tach at its connector or remove the + coil wire and temporarily wire 12 v.

You can also install a new tach from rccinnovations and avoid that whole issue.

 

delawarebill

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'73 fastback, 302 auto. new paint and all the interior re-done. new tires/wheels
[url=https://ibb.co/nRVcVLd][img]https://i.ibb.co/yVMyMQv/side.png[/img][/url]
i'm using one on my '73 also. got it from my brother and was on the shelf and i don't know which one it is... i am using the same wiring that was there and no mod's. works great even with the reduced voltage.. 2 yrs now no issues.

 

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