COMP Cams High Energy Alum Rocker SBC 1.These High Energy 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. 6 ratio, the die cast, larger than stock body of the Rocker arms is made of aluminum for superior strength with light overall weight. High Energy Die Cast Aluminum Roller Rocker Arms from COMP Cams are an affordable option that feature a die cast, aluminum body with a needle bearing