I have a buddy that has a Brison 2.4 and he was getting 7900 out of a 20-8 Pro Zinger. Timing advanced 4 turns.

I have a Fox 2.4 with the timing advanced 3 turns and I was running the same prop at 7650. I just put a Mejlik 21-8 on it to slow it down. I have this engine in my H9 Cap and I love it.

http://www.ros********.com/cap232pics/index.htm