I don't think its a good idea. I have a TH 75 in my Stuka. I have watched Easy Sports fly at our field. They are a floater for landing and they are fast with a 40 and very fast with a 46 engine. I think the 75 would WAY over power it!! Overpowering planes makes it harder to get them to slow down. They will want to keep cruising along and may have trouble losing altitude to land. Also the 75 uses a lot more fuel than a 40/46 so if you go with a 10 oz. fuel tank you can expect short flight times. If you really want to try it, I would suggest flying the ES plane with the 46 engine first and get it trimmed out. Get used to how it handles and how it lands. Then when you switch engines you at least are starting with a trimmed out plane that you have experience with. I am guessing that once you see how fast the plane is with the 46 engine, you will be too nervous to try flying it with a bigger engine! [8D]