Competition Cams 1441-KIT Magnum Roller 1.6 ratio, 3/8" Stud Diameter Rocker Arm Kit for Oldsmobile 350 and 403c.i. V8 Engines Kit includes Magnum Rockers, High EnergyPushrods, Rocker Arm Studs and Guide Plates Ultimate street rocker designed for serious performance enthusiasts Constructed from 8620 chromemoly steel, a superior material that will not flex and assures maximum lift Roller tip reduces friction while stiff design and superior ratio accuracy yields more effective valve lift 15 to 30 horsepower increase over stock rocker arms