The 4-valve M8 cylinder head flows considerably more air than previous 2-valve heads – but it needs to, to support today’s larger engines. Flow testing the stock heads shows an imbalance between intake and exhaust flow ratios. Our combination of qualifying seat installation, CNC porting, professional seat and guide finishing with oversize valves, careful spring set up and decking ensures you will extract maximum power from your engine modifications while improving the flow imbalance. This work is performed on your supplied head cores.