Ford Racing's premium roller rocker arm utilize high quality materials for a lightweight durable valve action.  The roller rocker arms by Ford Racing feature the following:

• Strong and lightweight aluminum construction
• Carefully machined to exacting tolerances
• Quality needle bearings for low friction high performance durability
• 1.65:1 ratio
• Stud mount for inline valves
  
• 7/16" stud mount intake rocker with .150" offset pushrod cup (pkg. of 16).
• Fits 289/302/351W and Ford Racing Z304D Aluminum Cylinder Heads. (For Z304 cylinder heads use M-6564-K351)