axial flow rotary valve engine head for a 2.8L 1999 BMW 328iS. It's fully integrated using the stock sensors, ECU, emissions equipment and exhaust. Uses 6 rotating tubes to let the air in and out of the engine, so they double as your camshaft. 3 rotate clockwise, 3 rotate counter clockwise since the belt/(later changed to a chain) wraps over and under each adjacent valve. It has real muffler bearings.