Cylinder Head Style:Assembled
Cylinder Head Material:Aluminum
Cylinder Head Finish:Natural
Combustion Chamber Volume (cc):69
CNC-Machined Combustion Chamber:Yes
Intake Runner Volume (cc):255cc
Exhaust Runner Volume (cc):87cc
CNC-Machined Intake Runner:Yes
CNC-Machined Exhaust Runner:Yes
Combustion Chamber Style:Heart
Intake Port Shape:Square
Intake Port Location:Standard
Exhaust Port Shape:Oval
Exhaust Port Location:Standard
Spark Plug Style:Angle
Intake Valves Included:Yes
Intake Valve Diameter (in):2.165 in.
Exhaust Valves Included:Yes
Exhaust Valve Diameter (in):1.600 in.
Valve Springs Included:Yes
Maximum Valve Lift (in):0.625 in.
Outside Diameter of Outer Spring (in):1.300 in.
Damper Spring Included:No
Number of Springs Per Valve:Dual
Retainer Material:Chromoly steel
Lock Style:7 degree
Valve Stem Seals Included:Yes
Rocker Arm Studs Included:No
Rocker Arms Included:No
Rocker Arm Nuts Included:No
Guideplate Pushrod Size:5/16 in.
Accessory Bolt Holes Drilled:Yes
Intake Valve Angle:12
Exhaust Valve Angle:12
Valve Guides Included:Yes
Valve Guide Material:Powdered metal
Valve Seats Machined:Yes
Valve Seat Machine Style:3-angle
Valve Seat Material:Ductile iron
Steam Holes Drilled:No
Oiling Style:Through pushrod
Machined for O-Ring:No
Notes: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.
Trick Flow engineers combined the best features of factory GM LS3 and LS7 cylinder heads with their own race-winning engineering and technology to create the ultimate square port LS cylinder head for 4.000″ and larger bore engines—the GenX® 255. Trick Flow GenX 255 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. Trick Flow GenX 255 heads are available with standard or 6-bolt per cylinder mounting patterns. The heads are available fully assembled or as bare castings.