RE: 4* 40 engine position
All of the 4 star 40's I have built, 3 kits and 1 ARF, required about that much wood be removed from the right cheek to clear the muffler. All of those planes had .46FX's on them and they all flew great.
Get ready because the 4 star .40 with a ball bearing .46 is simply the best combination of slow speed easy flying fun and high speed nail biting excitement you can get with one airplane. I have a friend that is a cop that also flies with us, he came out with the cruiser to the field one afternoon and we all took turns flying at his radar gun. My dad's 4 star clocked 95 mph in level flight which is nothing to sneeze at.
You will love that plane once you get it done and in the air.