RE: WM Dago Red and Jett 60LX?
I wouldn''t use an extension on this plane. You only have to tilt the engine ever so slightly to get the muffler to clear. You will already be moving the mounting holes because the muffler won''t work at all in the stock possition, which had the muffler coming out the bottom of the plane.
It is my belief that an extension is a fix for a problem. The engine and muffler were designed as a unit and adding an extension has got to mess with that at least some. Trust me, you won''t need the extension.
Blessings, Terry