These COMP Cams Ultra-Gold aluminum roller rocker arms with a 7/16 inches stud diameter and 1.73 ratio are designed for 351 Cleveland Ford applications. The new modern design features of these Ultra-Gold rockers are proven to withstand extremely aggressive spring pressure and value lift. Designed specifically for high performance street and race engines, the Ultra-Gold aluminum rocker arms are precision CNC-machined to strict tolerances. Developed to meet the demands of professional engine builders, these rockers include features never before possible in an aluminum rocker arm.