RE: Motor size for GP Extra 300s 40
Bret...I have a 4-stroke .91 in my Extra, I only cut out pretty much exactly what your expecting too. I had no prob. The most important area of that cowling to cut out though is the venting, on that one it's underneath in the area of that landing gear. You'll know what I mean though. It should have more area cut out of it then anywhere else. There's a pattern somewhere in the manual I believe that gives you a guide on cutting that part of the cowling.