retorque heads to solve issue?

dano said
Define "soot". Soot to me would mean exhaust carbon "Chalk" which wouldn't be the head gasket unless something was really wrong.

Is the build up moving or growing?

Got a picture?

It's more like exhaust carbon. I wiped it more or less clean a couple weeks ago, then ran the car for about 80 miles. This is what it looks like now. You can barely see any deposits but there is a slight bit of carbon.