that is right, the case and the plain bearing need to be stock, other than that the needle valve, head, back plate, piston and liner can all be different. The only inspection John Moll does or any other CD is four things. We provide the fuel at our contests.
1) Using suction (no pressure systems)
2) Plain Bearing, Fox 35 Stunt engine
3) any airplane, but must have at least one wheel
4) .016 solid lines, 60 feet long
We had all sorts of combinations at the Ice-O-Lated contest but they all used suction fuel system with a Fox 35 stunt engine, plain bearing. This is really a fun event because you are not restricted to a lot of specific rules. I love the fact that everybody's airplane are all different.
Hope this helps
Fred