Hi Guys, I got to fly a gentleman's plane today with the 58 on a H9 Carden Yak. I'm very impressed with the power and smoothness, it was tuned right too, has a 23-8 Xoar prop and he says it tacks 7300. What most impressed me was the smoothness through out the whole throttle band, very electric like. Not like any 50 I've flown. With stock muffler and the wooden airframe the sound is very very low and good. Not sagging or burping in rolling maneuvers whatsoever.
This is a nice little engine and perfect on the Carden Yak, very solid match.

Thanks Ralph and Gerald for reporting the facts here. I look forward to an RPM reading with a Mejzlik 23-8.

Joe