This engine looks to be a little power house stock. Cost $129.00 in a G-45 trimmer. Prop range 16-8 to 18- 8.
No load engine RPM is 9500. Weight with mag, stock muffler, prop hub, zinger 16-8 prop and DuBro 3" spinner is 67 ounces about 4 lbs. This weight can be cut way down. This info was from a Stihl conversion web.( Hints and Tips for RC Modelling ) Pan down to Stihl conversions, I got mine yesterday, need to get to work on it.