360 engine vibration at ~3000rpm

move the crank front and back see how wore the thrust bearing is. That is probably your knock due to a balance problem. The converter under pressure will move the crank. I already had the welds on the balance slugs on the back of the crank hit the block. You admitted driving this car like this for miles . I would say the thrust bearing is waisted. Move the crank see how far it goes front to back.