NAGALANGIT88 Larry Renger, Former Cox Engineer, Designer of the Black Widow and QRC engines. Over the years, as well as producing millions of model engines Cox also produced a similar number of ready to fly (RTF) airplanes, as well as boats, cars, helicopters, and trains. This engine sold for just $3.95 and was the final nail in the coffin of many competitors whose engines were selling for substantially more. Acceptable performance can be had without nitromethane, although the engine will be very sensitive to needle adjustments making it more difficult to operate. Claims are that Mylar and Teflon are lighter and make the engine easier to start and go faster, but they do not last as long as the stainless ones. Very similar to the later QRC engine which reportedly worked better. These use an O-ring seal rather than a Teflon disk. 302 Pre 1955 Standard Head - Hemispherical shape - Low Compression - Smaller dia.|Slot In Meaning It! {Lessons|Classes} From The Oscars