Bob,
I have the RCV 1.20 for a long term project, but I have not run it yet. I am sure you are aware that they turn the prop at one-half their operating speed which means that they will swing a larger diameter prop and higher pitch than their displacement would otherwise suggest. The power output of these RCV engines is less than other 4-strokes of similar displacement. Still great for scale applications. There have been a number of reviews of these engines in the RC magazines. RCV also has a pretty neat website.