I seem to remember a Peugeot 205GTI years ago with a bad case of 'pinking'. It had been at a machine shop who had skimmed the head and faced the block, also fitted what turned out to be the wrong pistons. Anyway, our screw in flexible hose compression tester indicated 330psi and stuck up in the air by itself just like a hard**. We worked the compression ratio out to be 13:1, that engine would have run on diesel!!!. Ed Kaps