World's Best High Performance Street Rocker Arms COMP Cams® Magnum Roller Rockers are the ultimate street rocker. That's because they were designed with the serious performance enthusiast in mind. They will help your engine make more power and last longer. Magnum Roller Rocker Arms are: Strong Magnum Roller Rocker Arms are made from 8620 chromemoly steel. This makes them stronger than die-cast aluminum or stamped steel rockers. This superior material, along with the Magnum's super stiff design, assures maximum lift because this rocker arm will not flex. Accurate You can't get maximum horsepower from your engine if your rocker ratio is off. We checked other rockers and found rockers that were as much as . 040" short on lift. The Magnum Rockers are super accurate. They check dead on every time. Powerful The Magnum Roller Rockers can make between 15 and 30 horsepower over other rockers! Why? The secret is that not only does the roller tip reduce friction, the Magnum Rocker's incredibly stiff design and super accurate ratios yield more effective valve lift. Durable The roller tip design reduces friction by not scrubbing the valve end or pushing the valve stem hard against the valve guide. This in conjunction with the super strong design of the rocker makes for a simple, bulletproof, and cost effective combination. Magnum Roller Rockers can be used with all High Energy, Magnum, Xtreme Energy, XFI, Nitrous HP, Xtreme 4X4? and Xtreme Marine? Camshafts as well as any other hydraulic or solid cam where open spring pressures do not exceed 350 lbs.Pit Stop USA offers Comp Cams Magnum Steel Roller Rocker Arms (16) - Ford V8 289-351W (Rail Type) 1968-89 Rocker Stud: 3/8 Ratio: 1.6 1431-16 at low everyday prices. Be sure to check out all of our products from Comp Cams including Comp Cams Roller Tip Stamped Steel Rocker Arms - Small Block Ford.