The TACH-ADAPT unit I developed will work with both the 3-pin and 6-pin Porsche CDI boxes (HKZ units) and the MSD systems. In the case of the 3-pin CDI, it accepts the low-level signal from the points (or electronic ignitor) and in the case of the 6-pin CDI, it accepts the low-level TD (Tach Drive) signal that is generated within the 6-pin CDI. It will convert this low-level signal to a more robust signal that includes the high-voltage pulse the older tachometers are triggered by. Please contact me by email for details and any questions:
ratech@pacbell.net Thanks! --Bob