Trick Flow 6-Bolt LS3 255cc GenX Aluminum Cylinder Head LSX 255. 650 Lift Ti Ret. This product data sheet is originally written in English. These are the TFS GenX LS3 255cc intake runner aluminum heads with 6-bolt pattern for aftermarket blocks, 69cc chambers, titanium retainers. And a max lift of. 650 for hydraulic roller camshafts. Looking for serious LS3 horsepower? Trick Flow engineers combined the best features of factory GM LS3 and LS7 cylinder heads with Trick Flow’s own unique brand of race-winning engineering and technology to create the ultimate square port LS cylinder head for 4.000 and larger bore engines-the GenX® 255. The heads feature fully CNC Competition Ported runners with a premium high resolution surface finish for maximum airflow and performance potential. The valve angles have been changed from 15° to 12° to increase piston-to-valve clearance and allow the use of larger camshafts. The coolant holes through the head deck were redesigned to work with all LS head gasket and engine block combinations. Stock LS3 ports accommodate LS3-style intake manifolds and LS9/LSA blower assemblies. GenX 255 heads are available with standard and 6-bolt per cylinder mounting patterns. Cylinder heads are available fully assembled or as bare castings. Accessory Bolt Holes Drilled. Combustion Chamber Volume (cc). Exhaust Runner Volume (cc). Exhaust Valve Diameter (in). Intake Runner Volume (cc). Intake Valve Diameter (in). Maximum Valve Lift (in). Includes new rocker arm rail mounts for use with LS3 1.7 ratio rocker arms. OEM rocker arm rail mounts will not work with these heads. Does not fit 2010 and later Chevrolet Camaro OEM exhaust manifolds; aftermarket headers are required. Number of Springs Per Valve. Outside Diameter of Outer Spring (in). Rocker Arm Nut Thread Size. Rocker Arm Nuts Included. Rocker Arm Studs Included. We do not lower invoice values since it is a violation of US and International custom laws. Let us work to resolve your problem so everyone is happy. Suite D7 Costa Mesa, CA 92627. TREperformance 1725 Monrovia Ave. Price Listed is PER HEAD.