Boyesen RAD-04A Rad Valve The rad valve's seamless, one-piece, precision casting and continuous aero form surfaces ensure maximum flow velocities and instant, explosive movement of air particles the moment you turn the throttle Integrated seamless inner chamber are 4-way aerodynamic directional dividers that distribute the angled charge evenly without flow loss Each Boyesen rad valve is unique, tailor made to that model, year and displacement 1-piece aluminum casting; no manifolds to trim or plastic pieces to insert Boyesen Pro Series rad reeds included