While trying some more suggestions for troubleshooting my idle vibrations, I connected a tachometer instrument to neg. terminal on the ingition coil and the other wire to ground as instructions said.
While reading the tachometer I see very signifcant fluctuations, see video.
Is this correct or what might be wrong with the ignition?
It depends, but if I recall the previous posts, this is a stock 1978 360.
We're seeing idle fluctuating between 1250 and 1500 rpm. The movement of 250 rpm is a little more than I'd like to see but not surprising in conjunction with your other observations.
That isn't the correct slow idle speed though. It might be correct for an engine warming up after kicking it down to the 1st step.
Has the AIR injection tubing been fixed or plugged?
