I have the GP Fabric covered Cub and I am running the OS FS81 in it it is a four stroke...As some others have said Cubs really suit four stroke motors...There is nothing like the sound of a Cub purring by when it has a four stroke motor in it...I like the OS because it is a very clean running motor...It recycles its crank vent oil..Instead of blowing it out the bottom and all over the plane it recycles it and lubricates itself etc....It is especially nice with the fabric covering as it is a little harder to keep clean...The 81 is a bit more motor than you need but if you ever fly floats you will be happy to have the extra power...I have never been sorry to have this motor..I think it is a very good match.. I am glad to hear that you are going to get some help getting this plane in the air...It is a beautiful plane and it is worth taking your time to learn how to handle it properly...You can learn more about flying with a Cub than you can with most planes....They are very easy to fly but they can bite you on the butt if you aren't carefull ...