will original tach work with electronic ignition, and how is it connected?

[70rag]

 

[Adam]

Yes, electronic ignition began in 71 or 72. In a factory set up the white tach wire goes to the negative side of the coil. Being that the Promaster is still just a coil I bet it would work. You could test it with a cheap tach, or multimeter (one that has 4,6,8 cyl settings) before hooking up the factory tach.

 

[moparleo]

The Mopar electronic ignition was not standard until late 1972. Factory tachs were not designed for electronic ignition. You need to either get a tachometer adapter to alter the tach signal or convert your tach with a new electronic circuit board. Most guys have to upgrade their tachs anyway as they are not very accurate or reliable.
Tachometer Repair Restoration for Chrysler Classic Cars

 

[Adam]

There is no difference in the tach itself, with or without, electronic ignition. But Leo makes a good point that the factory tachs are not very accurate. You should seriously consider an upgrade like this:RTE 67-74 Tach kit - rte

I have installed a couple of these, they are not difficult. You do have to solder some wires and calibrate it, but the directions are excellent.

 

[70rag]

Thanks so much....just ordered the kit.