AEM Tru-Time adjustable cam gears enable an engine's cam timing to match its tuning state, whether it is stock, modified, forced-induction or normally-aspirated. These cam gears are used by top race teams throughout the world and are a must for applications where the cylinder head or block is milled or where aftermarket or reground camshafts are installed. Our gears are the most durable on the market-we have cam gears on high performance engines that have run 100,000 miles with no wearing of the belt or belt surface. AEM cam gears feature true laser-etched markings and precision cut gear teeth that are guaranteed to match the Original Equipment (O.E.) drive tooth profile. Each kit includes comprehensive installation instructions, recommended cam gear settings and AEM decals.