COMP Cams Lifters 15853-12 Innovative design from COMP Cams takes both the performance and durability of GM Hydraulic Roller lifters to a whole new level. With continuous advancements in valve train technology, engine builders and performance enthusiasts alike are witnessing more aggressive cam profiles, higher valve spring pressures and higher engine rpm. Far too often, Hydraulic lifters get caught in the middle of these competitive valve train innovations. That's why engineers at COMP Cams developed the Short Travel Race Hydraulic Roller Lifters using a patent-pending design to maximize the performance of Hydraulic Roller lifters at higher engine speeds. When performance engines are equipped with Hydraulic lifters, high rpm is limited by the incorrect position of the lifter's internal piston, as the lifter inevitably ?pumps up?. This improper location results in open valves and therefore leads to lost power or sometimes even engine failure. The COMP Cams Short Travel Race Hydraulic Roller Lifters limit that internal movement to a minimum, which cuts down on these issues and allows higher engine rpm. The surface of this newly-designed lifter is REM-finished and then black oxided to significantly reduce surface friction, wear and lubrication temperatures. This creates not only a high performance component but an attractive one as well. The patent-pending Short Travel Race Hydraulic Roller Lifters are available for GM SBC, LS and BBC engine applications. Lifters,SBC Retro-Fit HYD RLR Short Trav COMP Cams Short Travel Race Retro-Fit Hydraulic Roller Lifters for Small Block Chevy Engines with OE Flat Tappet Camshaft, Set of 12 COMP Cams LiftersSBC Retro-Fit Hyd Rlr