Torres,
I believe that there was a Pawnee converted in the early 90's with a Chev 350 all alloy job built by a well renowned marine race engine builder.Looked like a neat conversion,Predator carb,extractors,exhaust all the way to the tailwheel,full electronic ignition etc.I believe also that this A/C may still be plying the paddocks around Port Lincoln way,stand to be corrected though!