Chevy LS3 Rectangle Port Bare Aluminum Cylinder Head 255cc/72cc E42006. This product data sheet is originally written in English. Bous Performance aluminum cylinder heads offer horsepower, torque and performance that your LS engine is capable of achieving. Features a raised rocker rail for improved rocker arm/valve cover clearance. Our cylinder heads have been carefully designed to achieve the economic growth from a cylinder head right out of the box, and yielding larger capabilities of port velocity with potential of more flow volume with intake and exhaust runners, with room for a CNC program that blends the bowls and Port matching the for greater forced induction of our cylinder heads throughout the RPM range. Designed for 4.00 or larger Cylinder Bore. 12 degree Valve Angle. Uses 2.165/1.600 intake & exhaust valves. 2.60” x 1.30” Intake ports. Require rocker mount for use with stock rockers. Valve guides and seats installed. Standard intake and exhaust port locations. Overview: Cylinder Head Material: Aluminum Combustion Chamber Volume (cc): 62 Intake Runner Volume (cc): 255 Combustion Chamber Style: Open Intake Port Shape: Rectangle Port Intake Port Location: Standard Exhaust Port Shape: Round Exhaust Port Location: Standard Oiling Style: Through Pushrod. Intake Valve Diameter (in): 2.055′. Exhaust Valve Diameter (in): 1.600′. Chevy LS3 Rectangle Port Bare Aluminum Cylinder Head 255cc/72cc E42006 Bous Performance aluminum cylinder heads offer horsepower, torque and performance that your LS engine is capable of achieving. Designed for 4.00 or larger Cylinder Bore Uses 2.165/1.600 intake & exhaust valves Require rocker mount for use with stock rockers Stan. LS1 Bare Cylinder head. Valve Seats & Guides installed.