ATK High Performance LS3/L92 255cc Aluminum Cylinder Heads

ATK high performance LS3/L92 25cc as cast aluminum cylinder heads are the perfect budget option for your next LS build. These fully assembled heads are capable of making over 600 hp naturally aspirated out of the box and will come loaded with upgraded components. The springs are set up to be used on up to .650 in. lift camshafts. No reason to swap parts on your new heads when running an upgraded cam! -- Features and benefits: * Bronze valve guides * Dual valve springs for .650 in. max lift * CNC-finished faces and bolt holes for extreme accuracy * 355-T6 high density aluminum * Machined for screw in studs and guide plates * All factory components will fit without modification -- Cylinder Head Specifications INTAKE: * Intake Runner Volume (cc): 252 * Intake Port Location: Standard * Intake Valves Included: Yes * Intake Valve Diameter (in): 2.160 in. EXHAUST: * Runner Volume (cc): 78.8 * Exhaust Valve Diameter (in): 1.600 in. * Exhaust Valves Included: Yes * Exhaust Runner: No * Port Shape: Round * Exhaust Port Location: Standard COMBUSTION CHAMBER: * Combustion Chamber Volume (cc): 69.4 * CNC-Machined Combustion Chamber: No VALVE SPECS: * Intake Valve Angle: 12 degrees (3 degrees rolled) * Exhaust Valve Angle: 12 degrees (3 degrees rolled) * Valve Guides Included: Yes * Valve Guide Material: Manganese Bronze * Valve Seats Machined: Yes * Valve Seat Machine Style: 5-Angle * Valve Seat Material: Chrome Nickle * Valve Stem Seals Included: Yes * Valve Stem Seal Style: Viton® Fluoroelastomer SPRINGS: * Valve Springs Included: Yes * Maximum Valve Lift (in): .650 in. * Spring Pressure Open: 370 @ 1.150 * Spring Pressure Closed: 142 @ 1.800 * Outside Diameter of Outer Spring (in): 1.29 in. * Damper Spring Included: Yes * Number of Springs per Valve: Dual * Retainers Included: Yes * Retainer Material: Chromoly Steel * Locks Included: Yes * Lock Style: 7 Degree ROCKER ARMS: * Rocker Arm Studs Included: No * Rocker Arms Included: N/A * Rocker Arm Nut Thread Size (in): 8 x 1.25 * Rocker Arm Nuts Included: No MISC: * Head Style: Assembled * Cylinder Head Material: Aluminum * Cylinder Head Finish: Natural * Spark Plug Style: Standard * Cover Mounting Style: Standard * Steam Holes Drilled: No * Oiling Style: Through Pushrod * Machined for O-Ring: No * Heat Crossover: No * 10mm Accessory Bolt Holes Machined On Ends of Heads Show Less