The McCoy Sportsman engines were all rear venturi engines. They were made from 1948 to 1949. Some were Ignition, and some were glow. They were more powerful than the front rotor McCoy "Stunt" and "Super Stunt" engines that followed them. The front rotor stunt and super stunt engines were made from 1950 -1955.
The McCoy co. bought out the Duromatic co. in 1956. The front rotor Redheads were produced from 1957 to 1966.
Dick McCoy made the first Red Head prototypes. The Red Head McCoys and the Johnson series of engines both used sintered iron pistons. The McCoys ran well, but wore out quicker than the Johnsons. The McCoys MAY have had a cylinder made of softer metal that made the McCoys wear out sooner.
The McCoy series 21 series followed the redheads. They were ringed and overweight, but ran well . Wild Bill Netzeband designed the interiors, and an unknown artist designed the exteriors making them heavy. (but streamlined looking )