[Modena]

Yes of course the cam sensor reveals cam position, but as the cam turns one time for every two crank revolutions, I would think the cam sensor is the signal being used to gauge and output crank RPM, because LS engines output one pulse for every 2 crank revolutions, in other words you set your tach to 4-cylinder mode.

Anyway this is not helpful to your issue I know! I would test mine for you but mine has never even been turned over yet so who knows, and it's not in a position for me to hook it up right now.