Comp Cams 54-459-11 LSR Cathedral Port 231/239 Camshaft for 1997+ Gen III IV GM LS EnginesLSR Cathedral Port 231 239 Hydraulic Roller Cam for GM LS GEN III IV Very wide power range and excellent midrange torque for LS engines with cathedral port cylinder head. Grind Number: 281LR HR 13 Engine Family: GM LS GEN III IV 3 Bolt 8 Cylinder (1997 2015) RPM Operating Range: 2,000 7,000 Cam Type: Hydraulic Roller Lifter Style: Hydraulic Roller Camshaft Series: LSR Cathedral Port All Out Power Camshaft Gear Attachment: 3 Bolt Valve Springs