Ok, I've read that 4 cylinder tachs the RPM reading will double if you run it on a V8 and a 6 cylinder adds 2/3rds.
I am running the MSD magnetic trigger and using the green and violet from the box and the manual says to use one of these
they say this: If you are using the magnetic pickup input (green and violet wires) to trigger your MSD Ignition, you will need one of these tach adapters. These units will correct the operation of most voltage-triggered tachometers that do not work directly off of the tach output terminal of your MSD unit.
Our tachs will run from the tach plug off the MSD box, it just reads more then the actual rpm's if you have more cylinders.
Will this MSD Tach adaptor run my RPM's correctly?