When the engineers at GM developed the LS series of engines, they provided enthusiasts with the most technologically advanced small block Chevy ever. Now, Trick Flow has raised the bar of Serious Horsepower and developed new LSX cylinder heads that significantly increase the performance of late model GM musclecars. During the development stage of the Trick Flow GenX Street/Strip CNC Ported cylinder heads, Trick Flow engineers determined the valve angles needed to change from 15 to 13.5 degrees to decrease valve shrouding, increase mid-lift airflow, and improve rocker arm-to-valve cover clearance. Testing also proved that relocating the spark plugs in the combustion chambers further enhanced mid-lift airflow and increased the rigidity of the casting for extreme horsepower applications. Furthermore, additional material was added to the rocker arm mounting points for high-rpm valvetrain stability. These fully CNC-ported performance cylinder heads feature 215cc (LS1), 225cc (LS2), or 235/245cc (LSX) intake runners, 80cc exhaust runners, 64cc (215cc head), 65cc (225cc head), or 70cc (235/245cc head) combustion chambers, 2.040 in. (LS1), 2.055 in. (LS2), or 2.080 in. (LSX) intake valves, 1.575 in. (LS1/LS2) or 1.600 in. (LSX) exhaust valves, bronze valve guides, and ductile iron intake and exhaust valve seat inserts. All TrickFlow Cylinder Heads purchased from Vengeance Racing come equipped with upgraded TEA 1.300 in. dual valve springs (for hydraulic roller camshafts up to 0.650 in. of valve lift),Viton fluoroelastomer canister-style valve seals, 7 degree machined steel valve locks, and 7 degree titanium retainers.