I didn't say anything about the Type 21. They came out in 1971 and were the worst of the bunch. The straw that broke the camel's back as they say. They came out in 1971 and disappeared shortly thereafter. They were the engine that put McCoy out of business for good. One of the engine guys, George Aldrich, even called them Junk in a column. They had the same one piece cylinder which was zinc plated. The aluminum piston has a single Dykes ring. They wore even faster then the old red and blue heads. I have a box of them in the basement. Again, none of them had sleeves. They all had one piece steel cylinders with integral fines. All made from one piece. Just like Johnson, K&B, OK and several other engines of the day.

The old redhead/Testors came out in 1957. They were around in some form or another until 1970 as headheads, blue heads and with and without lightning bolts. The parts were all interchangable and all were worth exactly what you paid for them. $4.95 for the 19 and $5.95 for the 29/35. The prices did go up during their run but compared to the other engines of the day they were DIRT cheap. If you didn't know better or couldn't afford better, you bought a McCoy. This excludes the old Duromatic 60 which was THE class "C" speed engine until the late 60's when it was overtaken by Dooling and some of the later screamers.

The first Testors had the plug centered and had no bosses on the venturi. After that, in 58, the plug was offset and the venturi had bosses where the spray bar went through. Other than the lightening bolt, color changes, and R/C carbs on the blue ones, they were the same engines.