Edelbrock part #77791 Red Roller Rocker arms are designed for Big Block Chevy’s using 7/16″ studs. This 1.7:1 Ratio, single replacement rocker is manufactured in the USA from lightweight 7129 grade aluminum. The body is CNC machined then micro polished and anodized for durability. The trunnion race, roller pin and roller tip are centerless ground for superior quality. A high…