I should have mentioned that is IS possible to set up a Corvair to run backwards, but you really don't want to do that, for reasons like cam gear thrust problems. Some sand dragsters do it to enable them to use VW transaxles without flipping the ring gear, but it's not entirely trivial, and not something I'd want to do in an airplane engine. Especially just to use a certain propeller!
Mark Langford, Huntsville, AL N56ML at hiwaay.net see KR2S project N56ML at http://home.hiwaay.net/~langford
