Thanks guys....Yes, this is the old Sig kit. A jillion pieces but only a century and a half to build. As a matter of fact, I framed this plane 15 years ago. It has been sitting in the top of my closet ever since. I got sidetracked a while but I'm back. Eight grandkids and two of them want to see my planes fly. I have never owned a four stroke until now but I have heard nothing but good about them. I bought this OS 48 specifically for this cub based on what the kit recommended. I really want to stick with a 4 stroke because of the sound and better fuel consumption. Perhaps I should consider a smaller 4 stroke. I do not want the plane to be out of scale either in performance or appearance. That may also prevent me from having to move the firewall. Buzzard.....Was your Champ a kit or scratch built? I own a full size Champ and would love to find a kit. I am not much on scratch building. Please let me know if there is a Champ kit available. Thanks again.