HPLS3270 Aluminum Cylinder Head for GM Gen III/IV LS Engines, LS3 Rectangle Ports [CNC Ported]

Name: HPLS3270 Aluminum Cylinder Head for GM Gen III/IV LS Engines, LS3 Rectangle Ports [CNC Ported]
Brand: ATK ENGINES
SKU: 059-HPLS3270
Price: 1239.00 USD
Availability: InStock

^$1,239⁰⁰

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GM Gen III/IV LS

Aluminum CNC-Ported Cylinder Head

GM Gen III/IV LS Engines

LS3-Style Rectangle Ports

Combustion Chamber: 72 cc

Intake Valve: 2.165 in.

Exhaust Valve: 1.60 in.

Intake Port: 273 cc

Exhaust Port: Raised .125 in.

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ATK Engines HPLS3270 Aluminum Cylinder Head Specs:

Material: A356 Aluminum
Bolt Count: 6-Bolt Head
Intake Port Volume: 273 cc
Intake Port Dimension: 2.600 in. H x 1.400 in. W
Intake Port Location: Stock LS3 Port
Intake Valve Size: 2.165 in.
Intake Valve Material: Stainless Steel
Exhaust Port Volume: 108 cc
Exhaust Port Dimension: 1.772 in. H x 1.882 in. W
Exhaust Port Location: .125 in. Raised
Exhaust Valve Size: 1.60 in.
Exhaust Valve Material: Stainless Steel
Combustion Chamber Size: 72 cc
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 (Hyd. Roller)
Valve Spring Setup Height: 1.800 in.
Valve Spring Closed Pressure: 160 lbs. (w/Retainer)
Valve Spring Open Pressure: 1.200 in. .600 in. Lift 425lbs / 1.150 in. .650 in. Lift 445 lbs. (w/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: 4 in.
Flat Mill: .006 in. per cc
Spark Plug Dimensions: 14mm x .708 in. with tapered Seat
Torque Specifications: Based on Factory or Aftermarket Bolts/Studs

ATK Engines HPLS3270 Recommended Components:

Intake Port Gasket: Factory GM
Exhaust Port Gasket: Factory GM
Head Gasket Factory Block: GM 12610046 (sold separately)
Head Gasket Aftermarket Block: 4.125 in. Cometic MLX
Spark Plug Starting Range: NGK TR55 or equivalent (sold separately)
Lifters: .600 in. per applications (lifters w/aftermarket tie bar recommended)
Pushrods: 3/8 in. Pushrods are recommended (must check length)
Rocker Arms: OEM w/upgraded Trunnions or aftermarket

ATK Engines HPLS3270 Flow Data:

Flow Tested on a Super Flow SF600 bench with a 4.030 in. bore size @28 in. water. Clay intake radius was used, Flow tube was not used on the exhaust port.,

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Upgrade Your Cylinder Heads

ATK High-Performance Cylinder Heads save time and trouble sourcing cores and or waiting for machine shops. ATK has multiple head combinations. The valve springs provided are an upgrade to OEM and allow for the use of a Hydraulic Roller or Hydraulic Flat Tappet camshaft.

Part TypeCylinder Head

Product LineATK High-Performance Cylinder Heads

BrandATK ENGINES

Package Height8.1

Package Width10.9

Package Length22.4

Weight26.93 PG

Part CategoryPerformance Parts

Valve Springs IncludedYes

Cylinder Head MaterialAluminum

Rocker Arms IncludedNo

Intake Port Volume (Cc)273