Hi
You can use a pipe lenght of 17 3/4 to 18 inches from first baffle to glo plug, launch with the motor running in the fastes 4 cycle it will run in ,or just starting to crack back n forth in a 4-2. The motor will drop into a solid 4 cycle within 1/2 a lap after launch, then it will beep 2 cycle across the tops of the manouvers.
If the setup is flying too slow pitch the prop up..do not use the needle as a speed control.
If the setup is going too fast [pitch the prop down..do not turn the needle richer.

If the setup slows or sags in the tops of manouvers add nitro... If the setup runs too fast or charges thru manouvers  cut the nitro percentages. I use this setup with 5% nitro in cool months and then going to 10% in hotter months

Thanks Randy.  I have the header at full length.  If I need to trim to get the length of the pipe down should I cut the pipe?

James

Randy

Hey Randy:
Just want to make sure I am clear on proper way to measure the pipe length.
When you say "to the glow plug" you mean starting at the plug tip, measuring thru the combustion chamber and out of the exhaust port, right ??   
On my PA65RE, measuring from plug tip to exhaust port flange I get  about  1 5/8", does that sound about right ?