DarZeelon

Thank you for that information. I think I did something similar when I initially set mine up. I did use the prop I intended to run, and not a smaller pitch one to simulate unloading however.

My initial setup was on a 10x6 APC prop and 10% Nitro. With a Mac's 1 piece muffler it was tached (max) at 13,400 RPM. That gave me a baseline of what I wanted to improve upon.

I set a goal to gain 1000 RPM and move up 1 pitch size to a 7. Now perhaps this seems fool-hearty, or conservative, but it was my goal.

Replacing the 10x6 with a 10x7 APC I installed a Mac's header, sleeve and pipe. It took 4 runs, measured by a tach to achieve the 14,500 RPM. After each run I removed .25" of header for a total of about 1". The final run resulted in a nice transition from idle to WOT.

Granted, the motor mav have more in it (RPM wise) but I figured a conservative tune was better then nothing. If you feel what I did may be part of the problem I am having (WOT misfire) let me know and Ill start from scratch.

Tommy D