Comments on my 340 plug under mag

Modern engines pull in 10 or more degrees of ignition advance when going into gear. My 2001 Chevy 8.1 idles at 20 in neutral and 30 in gear. That 10 degree swing keeps the idle exactly the same in or out of gear. And you can’t see a change in the wideband, it might fluctuate 1 or 2 tenths of a point.