Competition Cams 19005-16 Ultra-Gold Aluminum Roller 1.6 Ratio, 7/16" Stud Diameter Rocker Arm for Small Block Chevrolet CNC-machined, lightweight design removes weight and yields unrivaled quality and ratio accuracy Designed for high performance street and race engines Precision-sorted trunion bearings withstand elevated valve spring pressure and valve lift Additional clearance, up to 1.650 inch O.D. valve spring