Here are some pics of my Mac 28 conversion. The conversion parts are from Carr Eng, except for the muffler, from Ken Lambert. Milling the fins off the flywheel was done by a fellow club member with a lathe, but this can be done by Dave Carr, also. I also put on an 11mm walbro carb. The combination works well, giving 7850rpm on an APC 16X8 prop on the first tank, then over 8000 as it begins to break in.