How to find the right Automotive Performance Rocker Arm Assemblies AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Automotive Performance Rocker Arm Assemblies
- Mounting type
- Match the mounting to the head: stud-mount, pedestal-mount or shaft-mount. Each type needs a different head interface and hardware.
- Rocker ratio
- Use the rocker ratio your cam was specified for, or recalculate valve lift and spring requirements for a different ratio. Ratio multiplies cam lift, which affects coil bind, retainer-to-seal clearance and piston-to-valve clearance.
- Trunnion bearing type
- For higher spring pressures, choose roller-bearing trunnions over stock bushings, or install a trunnion upgrade. Stock trunnion bushings in some engines, such as GM LS, wear out under performance valve springs.
- Valvetrain geometry
- Check that the rocker tip sweep is centered on the valve stem, and set pushrod length to suit. Bad geometry wears valve guides and reduces actual lift.
- Spring pressure rating
- Choose rockers rated for the spring pressure you are running. Lightweight rockers flex or break under race-level spring loads.
Brands that matter
- COMP Cams: Broad range from stock-replacement to race rocker systems.
- Crane Cams: Long-standing rocker arm and valvetrain maker.
- Harland Sharp: Aluminium roller rockers, including shaft systems.
- Jesel: High-end shaft rocker systems for racing.
- Crower: Race valvetrain, including rocker arms and shaft systems.
- Scorpion Performance: Roller rockers and shaft systems for domestic engines.
- Yella Terra: Roller rockers for LS and other modern engines.
What to avoid
- Changing rocker ratio without rechecking spring and piston-to-valve clearances.
- Leaving stock trunnions in place under much stiffer valve springs.
- Skipping a pushrod length check when changing rockers.