STOCK Trickflow GenX 205cc GM LS Vortec Truck CNC Ported Cylinder Head LSX. This product data sheet is originally written in English. These are the TFS GenX 205cc intake runner aluminum heads with 58cc chambers. Looking for serious LS horsepower? These Trick Flow GenX® 205 cathedral port cylinder heads for GM 4.8L/5.3L/5.7L LS Vortec engines are fully CNC-machined to significantly increase the performance of GM cars and trucks. Trick Flow engineers altered the valve angles from 15° to 13.5° to decrease valve shrouding, increase mid-lift airflow, and improve rocker arm-to-valve cover clearance. Material was added at the rocker arm mounting points to increase high-rpm valvetrain stability. The spark plugs were relocated in the CNC-profiled combustion chambers to enhance mid-lift airflow and increase the rigidity of the casting for extreme horsepower applications. Top-of-the-line CNC Competition Ported runners have a premium high resolution surface finish for maximum flow and performance. Cylinder heads are available fully assembled or as bare castings. Part Number: TFS-30510001-C00 Part Type: Cylinder Heads Product Line: Trick Flow® GenX® 205 Cylinder Heads for GM LS 4.8L/5.3L/5.7L (Vortec) UPC: 842645106682 Cylinder Head Style: Assembled Cylinder Head Material: Aluminum Cylinder Head Finish: Natural Combustion Chamber Volume (cc): 58 CNC-Machined Combustion Chamber: Yes Intake Runner Volume (cc): 205cc Exhaust Runner Volume (cc): 80cc CNC-Machined Intake Runner: Yes CNC-Machined Exhaust Runner: Yes Combustion Chamber Style: Heart Intake Port Shape: Cathedral Intake Port Location: Standard Exhaust Port Shape: Oval Exhaust Port Location: Standard Spark Plug Style: Angle Intake Valves Included: Yes Intake Valve Diameter (in): 2.000 in. Exhaust Valves Included: Yes Exhaust Valve Diameter (in): 1.575 in. Valve Springs Included: Yes Outside Diameter of Outer Spring (in): 1.300 in. CARB EO Number: D-747 (pdf). To see a list of qualifying vehicles, enter CARB EO Number D-747 Emissions: California EO Approved. 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. And no repairs will be provided, nor labor charges covered by TREperformance Inc. TREperformance 1725 Monrovia Ave. Price Listed is PER HEAD.