It only took me 16 years and passing through two cars ('64 Commander then the '63 Daytona), but I finally figured out the wiring diagram to run my tachometer with my Pertronix unit using the transistorized sender from Studebaker International. It's an all digital sender and doesn't use a transformer like the old sender did, so the wiring diagram had to change a bit. The tach wire from the sender has to go to the (-) side of the coil, and I soldiered in a 1/2 watt 1000k ohm resistor to minimize the needle "jitter". After that, using our rarely needed Penske ignition analyzer, I calibrated the sender. I now have all my instruments back in the Daytona, and the tach isn't a decorative piece anymore. I also had to compile a wiring diagram printout and put it in my shop manual.