Look at link in post #12.Is there a sneaky way to hot rod an A65? Maybe drop in a longer throw crank out of something? I ask because there’s a homebuilt Champ at my home field that just walks away from all the other A65 powered planes, including other Champs. It even out-revs an 85hp Cub on the same prop. We know where the engine came from (another Champ crushed in a hangar collapse) but apart from giving strong oil pressure and not making metal we haven’t dug too deep into the engine itself.