The modifications I did to the crankcase were not for power; just to reduce the weight. I never understood why Zenoah left those four ugly threaded bosses on the front of the engine when used as an airplane engine. So, I turned the crankshaft and crankcase around, cut the tail of the crankshaft off so it wouldn't protrude from the case, made a block off plug for that opening, and used the four threaded bosses as my mounting point for engine stand offs. The engine looks much more compact, and is lighter. I suppose I gained just a touch of power by eliminating the seal drag of one of the crankshaft seals, but it wouldn't be much...

The pics kind of tell the story if you study them.

AV8TOR