Very wide power range and excellent mid-range torque for LS engines with rectangular port cylinder heads. 2,000-7,000 RPM Operating Range 231/247 Duration at .050". 113 Degree Lobe Separation Angle 0.617/0.624 Valve Lift LS3/L92 Ready - The LSR Rectangular Port grinds are the best choice for 6.0 and 6.2 L LS engines with an LS3 or L92 rectangle port head. With a wider split between intake and exhaust duration, these grinds take full advantage of the superior airflow from rectangle port heads. Fit type: Vehicle Specific