I have concluded, possibly inaccurately, that the tach used on a 300D Turbo is electronic. Therefore, the infamous tach-amp, that never seems to work properly, takes the place of the signal generated from the distributor to the electronic-ignition box of a gasoline engine. The question then is: Would a tach from a 300D (5 cylinder) work on a 6 cylinder gasoline engine if wired to the distributor-to-electronic-ignition box?