Installed on a 1963 Ford 427 FE with a dual quad setup along with the Ignitor III 71281D. The coil mounts directly into an existing OEM style coil mount, but is not compatible with 6V ignition systems, eliminating the need for an external ballast resistor or resistor cable. The coil does not have a coil ring connector and you will lose the factory charging connector when using the coil with Pertronix Ignitor Rigs.