I have a Saito 1.00 in my spitfire and it flys fine. If you have no restriction on noise, run the engine without the silencer. Just run a straight pipe out of the cowell. It is not that much more noise than with it baffled. You have to run the low end a lot more rich. I also run 30% heli fuel in it. You also can run a 20 oz. Dubro fuel tank without very much cutting. My spit is over 100 mph.

Good luck with a very good flying airframe.