Davis Unified Ignition (D.U.I.) GM Racing Coil Kits are an exceptional upgrade over stock HEI, improving performance. Designed for a maximum output of 10,000 RPM’s, nearly twice the factory output. The high voltage coil allows spark plug gaps to be opened up to .055?, providing more complete fuel mixture for power and fuel efficiency. Brass terminals in the cap provide greater conductivity and resists corrosion longer. Kits include coil, cap, rotor and nylon retaining screws.