For aftermarket ignition conversions, some tachs work better than others. Some are sensitive enough that the reduced signal is enough to allow the tach to display. Some are oversensitive and need a resistor to reduce the signal slightly.

Some are not. This means using a "tach adapter" which is simply a transformer to boost the signal strength. If someone has one, maybe they could post the input/output specs. Should be able to find an equivalent at any electronics supply house.

However, not sure what tachs are what.

Sherwood