We had designed and prototyped original 4-cylinder opposed-piston gamma-type circulating flow Stirling engine (CFSE) with lead valves, 2-stage large heater for waste heat recovering from rectangular duct of hot gas flow. Prospected output is 7.5kW-e by IPM generator. This kinetic design has an advantage of compact, low vibration and high rotational speed. Main materials of cylinder, casing, manifold and piston are made by sand cast of AC4C-T6 or SCS13. Heater part of large heat transfer is composed by vended stainless fin tube of form rolling. Those engineering trials using reasonable materials and process are very important for mass-production of low cost and distribution to the market.