[Scott Stoneburg]

The reason I suggested removing the plugs and turning over with starter is because the noise seems to be more noticeable at lower rpm. With the plugs out the starter will spin the motor over easy. I don't know what else you can try without just removing the motor and pulling apart again.

[STEELCITYFIREBIRD]

Short(ground) or eliminating spark(pull plug wire) to one cylinder at a time, if the noise goes away, you found your problem hole/s, and possibly the misfire also if that is still present(based on RPM drop).

You can do this manually at home or take it to a shop with the equipment to data log the rpm drop of each cylinder.
Known as a cylinder kill or cylinder balance test.

I believe your only after a noise at this point? Misfire/shake at idle remediated.

Ignition base timing has been set at this point , correct?

FWIW ...From the video, I hear a wrist pin knock.

Wish you were close by, I'd gladly stop by.

Keep diggin!

[TedRamAirII]

I hear no abnormal noises when cranking it over without spark plugs installed. Does it have a knock when cranking, with them installed? I dont know about all that shaking, it should be smooth, as its all balanced and all. Has anyone "felt" the knock anywhere? or just hear it? Could it be the valley cover?