Empi Cylinder Heads GTV-2 Stage 3 Wedge Port 42x37.5 94mm Bore PairEmpi Cylinder Heads GTV 2 Stage 3 Wedge Port 42x37. 5 94mm Bore Pair Empi start with the best in class EMPI GTV 2 Cylinder head casting and let a 5 Axis CNC Mill work it's magic to increase flow. Resulting in the best bang for your buck in increased horsepower. Their programs cut the Intake, Exhaust and Chamber with CNC precision. You now have a smooth, ready to bolt on finished head. The GTV 2 Cylinder Head casting eliminates the need for any welding