Upgraded valve spring keeps the valves closed in high horsepower applications. These comp 910 valve springs are recommended if you are running stage 3 injectors performance injectors. These springs are a very important to prevent the valve from making contact with the piston. Good upgrade for all high horsepower engine for competition or street. If you are running more than 35 psi of boost, you are losing out on potential power resulting from weak valve springs. The factory valve spring is only rated at 71-79 lbs. of seat pressure, which is not enough to hold under higher than factory boost levels. These springs are rated for 99 lbs of seat pressure to ensure your boost is staying where it should, in the cylinder. Revolutionary design features, such as the harmonic resistant shape, Super Clean ovate wire material and reduced spring mass, allow the Beehive Springs to better control the valve with a minimum of spring pressure. The bottom line in increased valve train stability, yielding more usable rpm and more horsepower than you ever thought was possible. If spring design is the heart of spring making, then system-analysis is its soul. System-analysis is the investigation of the valve train components as a complete mechanism or system. It includes the study of spring performance as it relates dynamically to the interaction of the camshaft, lifter, push rod, rocker and valve in an engine while in operation. Understanding how a spring interacts with the entire valve train system is absolutely critical to designing an application-specific spring.