Katech, the only real C5-R timing chain, beware of copies.. Never broken in all of the C5-R racing and any durability testing, this easy replacement chain utilizes production sprockets (not included). This is the exact timing chain used in the Corvette Racing programs for C5-R, C6.R and C7.R. Also used in race cars from 1997-present in the ALMS and now in the United Sportscar series too. Also endurance races such as the 24 Hours of Le Mans and 24 Hours of Daytona and more. The Katech C5-R race timing chain gets proprietary features over the standard IWIS aftermarket LS chains which includes “fine blanked plates” and a proprietary pin coating. In addition because it replaces your production chain there is no need to clearance your oil pump like most double roller chains.