Proptop, thanks for the response. I have run this on the stand a couple of years ago for my neighbor and it seemed to run ok but I'll run it some more just to be sure. As far as the O.S. engine it is very old, probably late 60's or early 70's. It has an air bleed carb and a clamp-on style muffler. It also has a piston ring and a baffled piston. It runs real strong as well. I'll have to get some more run time on the Eagle before I decide. This is going in a brand new airframe so I just want to be safe.