For Big Block Ford 429-460 applications with 7/16" studs, 1.73 Ratio; Cost effective aluminum construction provides superior strength to weight ratio; Needle bearing fulcrum and roller tip reduce friction and lower oil temperatures for improved response and horsepower; Durable design increases valve lift while withstanding the rigors of moderate race use; Die-formed aluminum body is larger than stock, and may require modifications to stock valve covers for clearance.