Procomp Electronics Aluminum Roller Rockers are extruded from 6061 T6 Aluminum with larger needle bearing fulcrums that can withstand valve spring loads up to 600lbs. The extruded body has a tensile strength of over 60,000 PSI, ideally suited for use with Solid / Mechanical flat tappet and Hydraulic Roller Cams. They feature very precise valve operation, horsepower increases of 10-15, increases the valve train life dramatically, acceleration is more responsive, and the oil temp will run approximately 5-10 degrees cooler.