Percolation? Heat soak? Don't drive during summer??

The green is not the tach ground. Red is power, black is ground, green is negative side of coil and white or yellow is the light for the tach. Some tachs use blue for the coil negative but yours used green. It's even in the diagram you posted. So it was hooked up right. That is unless the green was also grounded, in which case that was incorrect. Green is negative side of the coil ONLY.