O.S. exhaust header (Manifold) for the OS 21RG-M and 21RG-MX Engines is constructed of aluminum. Unique bolt-on round port design. 180 degree U-bend. This product includes one exhaust manifold. Two hex mounting screws.
OS 21RG-M or MX engine.
Width of outside of U-bend: 57mm (2.24") Width of inside of U-bend: 25mm (0.99") Manifold pipe diameter: 16mm (0.63") C.D. between mounting holes: 24.5mm (0.97")