So your going to put a .51 in a .25 size plane? Well power would not be an issue but keep in mind unecessary weight kills a plane trying to do 3D. Will it fly the plane I am sure it will. Will you be able to float around as if it had a smaller engine I dont think so. I think an OS .32 would be a better choice if you want a little bit bigger engine.

If this is your first 3D plane try to match up the gear as best as possible to your plane. If not you could end up with a plane that will be a handful and have you disliking what would normally be a great flying plane.