BBC Ultra Pro Magnum XD R/A - 1.8 7/16

The COMP CAMS BBC Ultra Pro Magnum XD R/A rocker arm is a full-roller performance upgrade engineered for big block Chevy engines seeking serious valvetrain control and durability. Designed for builders and enthusiasts who demand precision in cylinder head conversion or complete engine builds, this 1.80 ratio rocker arm delivers the mechanical advantage needed to open and close large-displacement BBC intake and exhaust valves with consistency across the RPM band. The 7/16-inch stud mount configuration provides stable mounting directly to standard BBC cylinder heads without requiring adapter plates.

Built from chromoly steel, the BBC Ultra Pro Magnum XD rocker arm combines weight savings with superior fatigue resistance—critical attributes when handling high spring pressures and aggressive cam profiles typical in street performance and racing applications. The full-roller design eliminates friction at the valve stem contact point, reducing parasitic losses and allowing more of your engine's power to reach the wheels while extending valve and pushrod life. The 1.80 ratio multiplies pushrod lift by 80%, offering the geometry needed for large valve openings on modified big block heads while maintaining proper rocker geometry angles for optimal pushrod and valve stem interaction.

This rocker arm suits builders transitioning from stock 396/427/454 setups to high-performance roller cam systems, particularly those running aftermarket heads with larger valve packages or significantly increased valve lift. Installation requires standard BBC rocker stud hardware and is compatible with both traditional pushrod geometry and modern flat-tappet or roller cam profiles. Each rocker arm is sold individually, so builders should order a complete set (typically 16 pieces for a full big block engine). Proper initial setup, including correct pushrod length calculation and rocker arm geometry verification, ensures maximum performance and component longevity in any BBC power plant.