Crower 74711F Features:

Crower 74711F shaft-mounted rocker arm system for BBC World Products cast iron Merlin heads with 1-piece intake stands and 5/8 in. shafts Stainless steel rocker system with 1.650 intake and 1.650 exhaust ratios for steel-based valvetrain strength, rigidity, and accuracy Designed for track and endurance use, with strength retention at sustained high temperatures for longer service life than similar aluminum parts One-piece intake stands help simplify installation and trackside maintenance on Big Block Chevy applications using World Products cast iron Merlin heads

Shaft Rockers BBC World P 5/8 In. Shafts, 1-Piece Features:

• Stainless steel shaft-mounted rocker system for BBC World Products cast iron Merlin heads, 1.650 intake/exhaust ratio, 5/8 in. shafts
• One-piece intake stands for simplified setup, extreme rigidity and valvetrain accuracy under sustained high-rpm racing conditions
• Steel-based rocker design with longer service life than comparable aluminum components in high-heat dirt track and marine use
• Compatible with needle-bearing roller tip option for reduced friction, added horsepower, and lower valve guide and stem wear
• Lighter tip design supports improved valve control, higher RPM capability, and reduced spring operating heat for longer spring life