In your case, since it's louder when cold, and you have checked, tightened or replaced almost all other sources, I'm beginning to think you might have a case of good ole piston slap. Very common with the Mod motors due to the very short pistons. If that is what it comes down to, it is nothing to worry about, my current engine has sounded like an older Cummins Diesel since the day it was built (wrong). The noise is embarrasing but it makes a buttload of power. I know of more than one person with n/a engines who complained to Ford when they were new and Ford just told them it is common, not serious and sent them down the road.
That being said, what ever happened to JOESLIGHTNING, he is the one who started this thread?
Mike