Thank you for your interest in our Aftermarket Upgrade Kits for the Universal Atomic 4 engine. We are excited to be able to help you improve the perfomance and reliability of your engine and keep the fleet running strong well into the 21st century. Within this site, you will find information, drawings, and photographs which describe our Atomic 4 product offerings ... Electronic Ignition without Ballast Resistor, Fresh Water Cooling (Mechanical and Electric), Crankcase Ventilation, Oil Filter, Belt Tensioner, Thermostat, 1/2 Notch Lock, and a Propeller just for the Atomic 4. Each kit is specifically engineered for the Atomic 4 and comes with detailed instructions and all parts and hardware for a quick, easy and professional installation. I think you will find the information most helpful in your quest to extend the life of your engine as well as to improve operation.