'68-'95For 3/8" Studs / 1.6:1 Ratio Magnum Roller Rocker Arms. Magnum Roller Rockers are the ultimate street Rocker because they were designed with the Serious performance enthusiast in mind. They will help your engine make more power and last longer.Ultimate street Roller Rocker arm designed for Serious performance enthusiastsConstructed from 8620 chromemoly Steel, a superior material that will not flex and ensures maximum liftRoller tip reduces friction while stiff design and superior ratio accuracy yield more effective valve liftFor Applications with less than 350 lbs. of open spring pressure Also Available in Rocker/Pushrod Kits:289 c.i.d. / 302 c.i.d. ApplicationsRockers and High Energyâ„¢ Pushrods (For Flat Tappet Lifters)Rockers and Magnum (Heavy Duty) Pushrods (For Flat Tappet Lifters)Rockers and High Energyâ„¢ Pushrods (For Retro-Fit Hydraulic Roller Lifters)Rockers and High Energyâ„¢ Pushrods (For OE Hydraulic Roller Lifters)351 c.i.d. Windsor ApplicationsRockers and High Energyâ„¢ Pushrods (For Flat Tappet Lifters)Rockers and Magnum (Heavy Duty) Pushrods (For Flat Tappet Lifters)