I flew a McCoy 35 redhead in Old Time Stunt (on a Sterling Yak-9) for a couple of years and was quite pleased with it. I've flown the redhead 19's for several years and think they are perhaps a better engine than the 35. I got rid of all my McCoy 35's because Fox 35's do as well or better and one can get parts. I still have the 19's. I've flown the Series 21 40's some and was not well impressed with them, although they have their advocates.

So far as the age of the Fox stunt 35. I think it has evolved a little, but is basically the same engine as back when it had two backplate bolts and 4 head bolts. So I would call it the longest in continuous production US engine.