Thanks for all your responses... they are all good.

I don't want to spend more money on this plane and engine. I know the 46 FX is no powerhouse. I just wanted to find the max speed for this combo.

I know I'm running the engine a little rich still because I've been too chicken to go over the 11K RPM limit I've imposed on myself. The muffler baffle has already been taken out. I guess the next thing to do is to try to find the Max RPM - 300 RPM for each of my 10" props. Then I'll try it all again with higher Nitro content, after I finish my current gallon of 10% Nitro.

daven... It's good to hear some first hand experience with this combo. What fuel did you use and what RPM did you achieve? Did you have any problems cooling the engine? Mine is inverted and I cut out 2.8125 sq-in from the bottom of the cowl behind the head of the engine.

Thanks,
Juice