CHP full roller rocker system- 9/16" shafts Steel bridge supports- 1.72 ratio. Increased Stability and Top End Performance. Hardened Shafts. Rockers Extruded From 2024 Aluminum. Brand New Cadillac Designed Rockers, Not Refurbished Ford Parts. Push Rod End is Profiled for Additional Valve Cover Clearance. Part of CHP's "Cadillac Designed" Project in Partnership with Harland Sharp.