COMP Cams takes pride in having the finest Rocker arm Studs available on the market. The High Energyâ„¢ and Magnum Series Studs work well in Applications with moderate lifts and spring pressures and are available in the popular 3/8" and 7/16" sizes. When ultimate strength is required as with high rpm Roller Cam Applications, the Hi-Techâ„¢ Race Stud is the answer. This Stud has a thin jam nut for Rocker clearance, rolled threads for maximum contact and a ground-flat top so accurate valve adjustment can be achieved and maintained. The diameter of the jam nut is larger in order to spread the load over a larger area. All COMP Cams Studs have generous radii and a black oxide finish. Designed for ultimate strength and locking force High Energy and Magnum polylocks are best for moderate lift and spring pressure Applications Hi-Tech Polylocks work well in all high end Race applications. The Stud girdle polylocks are precision ground for minimum runout and tapered for extra strength in the locking area.Base ThreadPart #DescriptionDiameterLengthStud DiameterEffective Stud Length4507-8Hi-Tech Race Exhaust for 396-454 Chevrolet with Aluminum Head7/16"1.680"7/16"2.000"