Along these lines....I work on some 290cc opposed twin cylinder ex military drone engines..We use them in Reno style pylon races..The manufacturer has a dyno for testing..
The combustion chamber is off set in the cylinder, for a better angle on the rod..He says there is a measureable improvement on the dyno when the cylinders are set up so that the offsets are opposite for the best push on the rods...Something to try someday....
We get about 30 hp on methanol, 9000 rpm with a 24-28 carbon prop..234 mph...
Gasoline gave about 400 rpm less, with half the fuel consumption...
Our rules don't allow tuned pipes, just 8" stacks..I would really like to see what one of these would do with pipes..
The engine is piston ported, modified for 170 degrees intake duration and higher compression with extra boost ports..
The manufacturer tried a reed valve system, didn't like the way it worked for his application...
the drone flew 6 hour missions, so fuel economy was a consideration..