In various entries, for example, on Wikipedia to Muscle Cars or elsewhere, there is always the talk that many manufacturers in the 70s took away the compression in order to comply with exhaust gas values. Also, because of lead ban (first in the USA, later with us) the gasoline should have had at first less octane as before.http://motorlexikon.de/img.php4?fotos/gross/K/K208.jpg How was this handled with vehicles that needed the high octane number?