I finally did some prop testing today. First off, these numbers will not seem very high. I am at least 2+ inches too long on my header. Most people running the 58 with an ES composite pipe are at 11 or less, and a friend of mine says I should be around or below 10 inches.
You would not believe how quiet this pipe is, almost like an electric in the air. The throttle response and feel is no different than on a stock muffler, awesome.

Time permitting, I will start cutting 1/2 of an inch at a time until I hit max rpm or feel peakiness.
At this point I really do not need any more power from this engine, as it flies my EF Yak very well, and pulls it out of hover with authority. I am sure with tuning I can pull many more hundred rpm out of each of these props with no sweat.

This is a new 58 with less than 3 tanks through it. Karl Mueller header at 12.5 inches.
Edit:- Engine set rich d/t first run on a new engine with a pipe I have not experimented with before, better safe than sorry.


Vess 23a
stock muffler-7300+
Es composite-7600

Mejz 22x10
ES composite-7400

Menz-s 23x8
ES composite-7100

Nx 23x8
ES composite-7000+/-