I thank the car Gods that I have a 72 pre-L that has always been in CA and is exempt from the smog monster. However, back in the days when I did have to smog it there were other issues besides tailpipe emissions. In fact, I was able to pass smog easily without any tricky settings. Where I got in trouble was that the smog station noted that the law requires the stock air cleaner with all it's emission-related flaps, etc be installed. Mine was after market .. no stock one available. A friendly smog station would occasionally overlook that but as the smog police tightened the noose, I eventually parked it until the exempt time arrived.