Xtreme Energy™ Cams- These cams are COMP Cams® newest series of camshafts. They are designed to take advantage of the latest improvements in valve train components and the newest developments in camshaft design. Their aggressive lobe design produces better throttle response and top end horsepower than other cams with the same duration @.050", while delivering increased engine vacuum. These cams are designed for 1965-96 engines that were NOT originally equipped with a hydraulic roller cam.