I think that you'll wind up with more problems trying to use a car engine in a plane than it's worth. The drive hub is going to be a real issue. I also have doubts that the crankshaft is going to be long enough to get a drive hub, prop, and prop nut on it. But I think that biggest issue you will run into is going to be the muffler as it may turn out to difficult to mount it on the plane.

I could be wrong but I think you'll be better off just investing in an engine designed for a plane from the start. My dad always taught me to use the proper tool for the proper job.

Ken