These High Energyâ„¢ Die Cast Aluminum Roller Rocker Arms for Chevy V8 265-400 Applications are perfect for street and moderate Race use. With a 3/8" Stud diameter and 1.5 ratio, the die cast, larger-than-stock body of the Rocker arms is made of aluminum for superior strength with light overall weight. High Ener gyâ„¢ Die Cast Aluminum Roller Rocker Arms from COMP Cams are an affordable option that feature a die cast, aluminum body with a needle bearing fulcrum and Roller tip. Designed to be stiffer and more durable, these cost effective Rocker arms are capable of providing added valve lift while withs t anding the rigors of a performance application. Their specially engineered fulcrum and Roller tip create far less friction than sliding factory models to lower oil temperatures, thus improving both response and horsepower. Snap rings are used to hold the trunnion and bearings locked in place.< ul>< li> Cost effective aluminum construction provides superior strength to weight ratio< li> Needle bearing fulcrum and Roller tip reduce friction and lower oil temperatures for improved response and horsepower< li> Durable design increases valve lift while withstanding the rigors of moderate Race use< li> For use with up to 550 lbs of open spring pressure