I know the high end OS .15 airplane engine is a modded car engine. But remember the buggy engines are
built to rev in excess of 25,000 RPM. the .21 and .32 is exactly what it states a .21 or .32 CID engine.
If you plan to use a .32 or a .21 make sure it goes into a plane of that size. I don't know first hand the
effectiveness of running a high speed car engine at 10,000 rpm. I would reccomend getting a OS LA
series engine in your trainer before i would take the risk of putting the car engine in. And remember
airplane engines HP ratings are done in the 15-18k range where cars are done 25-30k and up. Porting
is significantly different, and car motors are run with gearing to keep the load low.