Have the Hangar 9 80" Cub, purchased used with a .61 two stroke in it. Was wayyyyy too much power for the Cub. Installed an OS .70 4-stroke and still too much power. Am planning on going with an OS.52 or a Thunder Tiger .54 4-stroke. You do not need alot of power for take-off and I rarely use what the .70 has available for flying, much less to get it off the ground. As a matter of fact it's tougher to get these Cubs to slow down with the larger engines and larger props, at idle, so you can get them BACK on the ground! You will find that even with the smaller .52 or .54 that most of the time you will be flying at reduced throttle settings and enjoying the plane.