How can you tell if a CH ignition is Syncro Spark? I understand those that are should be engraved "SS" Is the circuit board itself marked? I recently took apart an old brown box to replace wires and found SS written on the board. The ignition was on an engine that had mechanical advance and is ancient, maybe 1986 or so.

Thanks,

Greg

A CH syncro unit has 2 separate boards in the case. The HV CDI board and the timing board. So Non Syncro has 2 parts inside the box (board and coil) and the SS has 3 parts.

Great. Thank you.