stihl 039

Hi All, A newb question on modding a muffler on an MS390... I've had the saw for while now and done a fair amount of cutting with it but could always use more power :) I've been reading some of the other posts about the muffler mods and want to give it a crack, but was thinking to buy an...

I picked up an 039 for next to nothing, but it is trashed. I'm looking to rebuild and I was wondering if I should just replace the top end, or order an entire engine that is ready to install. The Piston is scored, and the rings are stuck. The jug is scored as well. I'm just wondering if I can...