No mods, just install it as per the instructions. You remove the points and condensor, and the module screws down to the breaker plate where the points did. And there's a magnetic rotor that fits over the points cam. Set the gap between the two at .030, replace the cap and rotor, hook the two wires up to the coil and you're done. I'd recommend a new cap, rotor, wires and plugs along with the conversion unit. I've gone with the newer big post type cap on mine. You can get the adapter, cap and larger rotor at your local parts house. I run Ford Racing 9mm wires on mine.