A pollutant of concern to the mankind is the exhaust noise in the internal combustion engine. However this noise can be reduced sufficiently by means of a well designed muffler. The suitable design and development will help to reduce the noise level, but at the same time the performance of the engine should not be hampered by the back pressure caused by the muffler. The authors designed and fabricated a reactive muffler and afterward compared the noise level, Brake thermal efficiency and Brake Specific Fuel Consumptions with the existing muffler and the modified designed and fabricated muffler.