I agree fully it's the coating that makes it work, normal pistons with an interference fit would mean seized city...When I was working for Ford back in the early 90's I started seeing manuals with interference fit specs & thought it had to be an error, but I visited the Lima Engine Facility & saw real examples of it... Also they were working toward having main bearing fasteners & head bolts all extended to the central mass area of the engine rather than just through the main caps/cylinder heads..Main Bearing Girdles are also common on newer engines...