YourDyno Universal Tach Pickup. MSD 8918. Works for most engines and dynos!

Nice cheap option for adding a versatile tach input to any datalogger, dyno, tachometer. I was happy to see that it worked on GM HEI, BMW COP, Commonrail Diesel(bosch), Old school VW. Anything with a coil driven injector or ignition coil!