Comp Cams LS1 Pro Magnum Lifters for hydraulic roller cams.

Chevrolet Small block 305 & 350. For use in blocks originally equipped with hydraulic roller cam. ('87 to present, and LS1)

These Comp Cams Pro Magnum hydraulic roller lifters are specifically designed to perform at higher engine speeds. When engines are equipped with a hydraulic roller camshaft, high rpm is limited by the improper position of the internal piston, as the lifter inevitably "pumps up". This improper location results in broken valves, and therefore leads to lost power or sometimes even engine failure. These lifters offer a distinct advantage over standard high-performance hydraulic lifters, especially in race applications where a hydraulic lifter must be used.