Possibly the most famous and successful of all model race car manufacturers, the Dooling brothers not only mass-produced seven different race cars of their own design, but also developed and marketed one of the finest high-performance miniature racing engines: the Dooling .61. The Dooling Brothers (Russell, Harris and Tom) produced a line of tether cars and engines in the 1940’s. The die cast racing engine was a rear disk rotary valve. The 1948 version of the engine had seven cylinder fins and one fin on the head as shown in this example, while the 1947 version had ten cylinder fins. This engine is missing the ignition points. Shown is an aircraft version but they were more widely used in tether cars. Also shown are five tiny vintage spark plugs made by Champion Spark Plugs for model engines. Champion no longer makes plugs this small, but a company called Rimfire Spark Plugs does make small plugs for this type of engine.