595 Hydraulic Roller For Chevrolet LS-Series. Stock valve springs cannot be used. Not compatible with Active Fuel Management (AFM). An AFM delete kit and/or disabling the AFM through the ECM is required. Intake vacuum may be too low for power brakes.Good Mid-Range torque 3,000-4,000 RPM. Operating power range between 2,200-5,400 RPM. Compression Ratio 10.5:1 to 11.0:1. Manual transmission or high stall automatic. Seat pressure 120# closed 300# open. 3.90:1 to 4.50:1 Axle Ratio. 050: Intake: 238° Exhaust: 242° Advertised Duration: Intake: 296° Exhaust: 299° Valve Lift: Intake. 595 Lobe Separation: Intake: 108° Exhaust: 116° Power Range: 3,000-7,000 Idle: Noticeable/Fair. In the event the item should fail due to manufacturing defects during intended use, we will replace the part by free. For more information, go to California goverment website, you can search California P65Warnings.