I was looking to get into gas engines. I found, and the general consensus is, that it just doesn't make any sense for a plane less than 30% scale - even the 25% planes don't benefit. The problem is the power to weight ratio - you have to add a lot of weight for a gas engine, and nitromethane has a lot more energy than gasoline, so you're losing on both accounts. Once you get to 40CC, the power to weight ratio starts to go the other way and you would benefit with a larger plane. The plane you have is supposed to be a great flier, but most likely only at the appropriate flying weight. Believe me, I understand the desire to get into a 'gasser', but definitely do some research and see what is to be said about them and the planes they belong in.

Things to consider are: was the plane meant to fly at that weight? It surely wouldn't fly like the Tiger 60 everyone knows and loves. Was the airframe designed to handle that much low-end torque? There's also a different amount of vibration, again was the plane meant to handle it?

Don't forget you would need to add more electronics (weight/batteries) for the ignition.

I tried and tried to find a good small plane to accept a 26cc gas engine, and kept hitting a dead end. The 25% are being flown with 1.60/1.80 glow, and the 33% are getting the smaller ->40cc gas engines.

Try an efficient four stroke - you will get low end power and fuel efficiency. If it makes you feel better I am running two 1.20 two strokes and 10% fuel here is $35 a gallon.