COMP Cams®’ Pro Magnum Hydraulic Lifters™ are specifically designed to perform at higher engine speeds. When engines are equipped with a hydraulic camshaft, high rpm is limited by the improper position of the 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. COMP Cams®’ Pro Magnum Hydraulic Lifters™ offer a distinct advantage over standard high performance hydraulic lifters, especially in race applications where a hydraulic lifter must be used. When tested in a Chevrolet 468 ci Big Block, the power increase was significant