At first it was in the upper 11K range, but it slowly crept up to 14K. I'll do another tach reading when I get it mounted back on the plane (broke the motor mount) just to see what it says. It's entirely possible that the reading may have been inaccurate for whatever reason; I'm used to larger engine RPM readings and at the time didn't think twice about the reading that I was getting. The OS literature says the max RPM is 16K and that I wouldn't see it on the ground, and since I was swinging the smaller break in prop I figured 14K wasn't out of line. I'll get back in the next couple days about what I find. In either case it does pull hard and I'm happy with whatever the RPM is, but I do want to make sure I'm quoting the right figure.