mustafagander
I do have an argument there mate!
There have been a few proven conversions out there involving automotive engines eg. Oliander V8 Chevrolet 454 engines fitted to Queenair airframes in Canada back in the mid 80's with full approval.
I do not know if you remember the Vickers Vimmy replica that flew all the way from England to Australia with god knows how many stops on the way due to speed but made it to Bankstown with two (again) V8 454 Chevrolet truck engines fitted. Low revving engines with no problems at all. I have seen internals of several Lyc/Con engines many times and they are no different to internals of most high performance automotive engines.
And when it comes to oils, it all depends on the application.