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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
Not Yet Reviewed
$748.99
ATK offers select parts for your build, including cylinder heads. They use them in their engine combinations and are available to complete your big block Chevy engine or upgrade existing components. ATK High Performance 290cc BBC cylinder head features: * A356 aluminum construction * Stainless steel intake and exhaust valves * Manganese Bronze valve guides * Viton® valve seal * Powder meatal valve seats * Steel retainers with 10-degree locks * Spark plug dimensions: 14mm x .708 in. with gasket seat
Not Yet Reviewed
$998.99
On Sale
ATK offers select parts for your build, including cylinder heads. They use them in their engine combinations and are available to complete your small block Ford engine or upgrade existing components. ATK High Performance 205cc SBF aluminum cylinder head features: * A356 aluminum construction * Stainless steel intake and exhaust valves * Manganese Bronze valve guides * Viton® valve seal * Powder meatal valve seats * Steel retainers with 7-degree bead lock keepers * Spark plug dimensions: 14mm x .750 in. with gasket seat * Head bolt diameter: 1/2 in.
Not Yet Reviewed
$698.99
$648.99
On Sale
Outfit your top end with a set of these assembled ATK High Performance aluminum cylinder heads for small block Chevrolet. They're cast, machined, and assembled with A356 aluminum alloy. The heads feature the latest port designs for maximum efficiency and increased power, and improved stock exhaust port location for better header fitment. ATK High Performance aluminum cylinder heads for small block Chevrolet include: * 2.020 in. stainless steel, swirl polished with undercut stem intake valves * 1.600 in. stainless steel, swirl polished with undercut stem exhaust valves * Manganese bronze valve guides * Alloy valve seats * 1.437 in. diameter valve springs (.600 in. max valve lift) * Chromoly 7-degree valve spring retainers * Single groove 7-degree valve locks * Valve spring locators * 5/16 in. flat pushrod guideplates * 3/8-24 in. rocker arm studs
Not Yet Reviewed
$798.99
$748.99
On Sale
ATK offers select parts for your build, including cylinder heads. They use them in their engine combinations and are available to complete your big block Chevy engine or upgrade existing components. ATK High Performance 315cc BBC cylinder head features: * A356 aluminum construction * Stainless steel intake and exhaust valves * Manganese Bronze valve guides * Viton® valve seal * Powder meatal valve seats * Steel retainers with 10-degree locks * Spark plug dimensions: 14mm x .708 in. with gasket seat
Not Yet Reviewed
$1,048.99
$998.99
ATK High Performance 250cc LS1/LS6 aluminum assembled engine cylinder heads are complete new builds. They include valves, valve springs, valve spring retainers, valve stem seals, and soft plugs. All threads are checked and repaired, if necessary; and all passages and part interfaces are pressure checked. Product specifications: * Material: A356 aluminum * Bolt count: 6-bolt head * Intake port volume: 250cc * Intake port dimension: 3.227 in. H x 1.119 in. W * Intake port location: Stock cathedral port * Intake valve size: 2.080 in. * Intake valve material: Stainless steel * Exhaust port volume: 105cc * Exhaust port dimension: 1.628 in. H x 1.722 in. W * Exhaust port location: .086 in. raised * Exhaust valve size: 1.60 in. * Exhaust valve material: Stainless steel * Combustion chamber size: 61cc * Valve cover bolt pattern: Perimeter bolt * Valve angle: 11 degree * Valve spring pocket diameter: 1.610 in. O.D. * Valve spring pac: 1905 dual spring (hydraulic roller) * Valve spring setup height: 1.800 in. * Valve spring closed pressure: 160 lbs. (with retainer) * Valve spring open pressure: 1.200 in., .600 in. lift, 425 lbs. / 1.150 in., .650 in., lift 445 lbs. (with retainer) * Valve spring max lift: .650 in. * Valve guide material: Manganese bronze * Valve seal material: Viton© * Valve seat material: Powder metal * Retainer material: Titanium * Deck thickness: .750 in. * Minimum bore diameter: 3.900 in. (will not fit stock bore 4.8L/5.3L) * Flat mill: .006 in. per cc * Spark plug dimensions: 14mm x .708 in. with tapered seat * Torque specifications per application based on factory or aftermarket bolts/studs
Not Yet Reviewed
$998.99
On Sale
ATK offers select parts for your build, including cylinder heads. They use them in their engine combinations and are available to complete your LS engine or upgrade existing components. ATK High Performance 260cc LS3 CNC-ported cylinder head features: * A356 aluminum construction * Stainless steel intake and exhaust valves * Manganese Bronze valve guides * Viton® valve seal * Powder meatal valve seats * Titanium retainers * Spark plug dimensions: 14mm x .708 in. with tapered seat
Not Yet Reviewed
$1,148.99
$1,098.99
ATK offers select parts for your build, including cylinder heads. They use them in their engine combinations and are available to complete your LS engine or upgrade existing components. ATK High Performance 270cc LS3 CNC-ported cylinder head features: * A356 aluminum construction * Stainless steel intake and exhaust valves * Manganese Bronze valve guides * Viton® valve seal * Powder meatal valve seats * Titanium retainers * Spark plug dimensions: 14mm x .708 in. with tapered seat
Not Yet Reviewed
$1,198.99
ATK offers select parts for your build, including cylinder heads. They use them in their engine combinations and are available to complete your small block Ford engine or upgrade existing components. ATK High Performance 185cc SBF aluminum cylinder head features: * A356 aluminum construction * Stainless steel intake and exhaust valves * Manganese Bronze valve guides * Viton® valve seal * Powder meatal valve seats * Steel retainers with 7-degree bead lock keepers * Spark plug dimensions: 14mm x .750 in. with gasket seat * Head bolt diameter: 1/2 in.
Not Yet Reviewed
$648.99
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