That's a good looking example from the pic. McCoy made the engine in the '50s. It's part of the Sportsman series, .19, 29 and .36. It takes 29% pure castor and 5 or 10% nitro. Anything else will ruin it. We used to use Nitro X or Fox Superfuel, but any will work in it as long as the mixture is correct. It does not have the power of the Fox .35, but will pull a moderately light plane, ie: Firecat, Ringmaster, Half fast, Yak 9 Etc with no problem. The Cu. In. is somewhere in the range of .325 whereas the Fox .35 is .352, however, even with that disparity, the McCoy "36" was the reason the AMA made the displacement limit for combat .36. Those who did not read the specs thought the McCoy had the advantage and should have been disqualified because the engine was a 36, not a 35 like the Fox. The limit at the time was .35 Cu. In.
I learned to fly "large" airplanes (bigger that 1/2 as) with a McCoy "36" on an ABC Trainer by Victor Stanzel. I then used it for other things until I could afford a Fox .35.
I you would like I can look for one for you at Perry and/or Toledo. Just let me know.
FWIW I have built an ABC Trainer and put a McCoy "36" on it and hope to bring it to Brodak this year.
Bob