THAT IS NOT WHAT IS GOING ON HERE!!!!
The Crane system here is very similar to MSD that is they are CD, and the switched wire for both IS ONLY A LOW CURRENT "power on" wire. The main current is fed to the box direct from battery
CD IGNITIONS DO NOT HAVE 12V FED TO THE COIL
On ANY CD system you DO NOT hook power to the coil and you do NOT hook the tach to the coil