The latest development in Rocker arm Technology from COMP Cams are Ultra Pro Magnumâ„¢ Rocker Arms built for 1/2" Studs to increase valve train stiffness and stability. Designed to be used in conjunction with the COMP Cams Hi-Tech 1/2" Rocker Stud Kit, the latest versions of COMP Cams Ultra Pro Magnum Rockers are built to utilize 1/2" Studs to stabilize BBC valve trains. Ultra Pro Magnumâ„¢ Roller Rocker Arms feature a modern arched, web-like design to deliver increased strength and rigidity while still reducing the moment of inertia and optimizing the dynamic balance. The Rockers also boast precision-sorted needle bearings and hardened Roller tips. And since they now feature the added benefit of accepting 1/2" Studs, they are a great choice for anyone looking for more stiffness with Stud mount Rockers. These new Ultra Pro Magnumâ„¢ Rocker Arms will provide the ultimate in valve train stability for maximum valve motion both at the track and on the street.1/2" Studs provide a stiffer valve train to achieve maximum valve motion in BBC enginesDeliver increased strength and rigidity while reducing the moment of inertia and optimizing dynamic balance