this is way beyond me as to why you would want to shoehorn a 110 (particularly a YS) into a 40 size plane. i'd recommend the 60 size just because 110 is way beyond the requirements of the 40 size. a lot of people put normal 91's in the p- 51s and that is already overpowered. plus, with that YS, how many minutes will you be able to fly on the stock tank? 4? go with the 60. if you really want speed, get a high performance 2 stroke, tuned pipe and a speed prop.