I have most of the plane together but I am experiencing an issue with the engine going. I am putting in an ABC .75 and with the engine in, the muffler does not marriage to the engine. I believe I will need to trim away some of the upper part of the cowl or try and find a muffler that will work with the engine and plane. Any suggestions? I might be able to rearrange the motor mount by rotating it a couple degrees and customizing the holes in the mount to fit.