Abstract: An improved inshot gas burner for use in gas furnaces, clothes dryers and other like gas appliances providing improved combustion flame characteristics. A novel burner body design is tuned at manufacture solely by the insertion therein of a flame retention device which has been configured, sized and shaped for the aerodynamic features thereof which will produce proper flame retention and burner fuel loading for the air flow characteristics of the particular appliance model in which the burner will be used. The gas burner is provided with an outwardly flared outlet port downstream of the flame retention device continuous with an outwardly flared diametrically opposed flame carry-over ports. These flared port constructions have produced superior flame characteristics, particularly when used in high-efficiency, forced draft furnaces.