Aluminum Full Roller rockers for the Hemi head, manufactured by NR Racing Rockers are crafted of aircraft grade billet aluminum and feature replaceable steel roller tips, 1.2 ratio. Dyno tested to 10,000 rpm and proven to make more horsepower May require valve cover spacer or minor grinding on valve cover grinder for clearance. Due to canted valve arrangement, Hemi's may have valve to piston clearance issue with high lift cam, esp with 1.2 Ratio. The engine builder needs to verify clearance! These Rocker Arms require shorter Pushrods, typically 5.260 or 5.340 depending on cam and head milling. Note: These are designed to work with standard length or +.070" valves, they are not recommended for the +.230" valves.