Has anyone installed an OEM Tach in a 68 ? I bought this 68 GT, but previous owner restored it using std dash cluster and std wire harnesses. I'm installing the GT dash cluster with Tach. I'm not going to spend mucho dollars converting back to the GT wire harness. I want to wire the Tach independent to the harness. I have figured out the wiring for the Alt-Oil lights, but the Tach has me stumped. Haven't found any factory wire diagrams that will help. I'm useing a Mallory electonic distributer and Mallary Coil. Will apprecite any help on this.

Don

 

hiya
the original tach is wired inline (totally different from the normal paralel setup at coil-). it goes like a cable extension between ignition switch and coil+
you know when you have key in ingition position it will feed 12V+ to the coil+. right behind the ignition switch (maybe 2inch) is a quick disconnect which at stock leads to the pink resistor wire. disconnect and place the tach inbetween

the bad news is: it might not work with your type of ignition (mallory). it only works if there's voltage going up and down at coil+ as the coil pulls it.
Well anyway givbe it a try at least ...

 

before

ignition switch ---[-----------------]firewall[------ coil+

after

ignition wsitch ----[----tach ---[-------------------]firewall .....

 

Thanks, I'll give that a try
Don