When you get in there, check the pads on the arms on the valve ends. They have a tendency to get worn or hammered by the valves . If yours are grooved then you will need narrow feelers to fit in the grooves.
My set-up was never really quiet, not loud either, but still audible.
I agree. I used to resurface the pad end with my Souix valve grinder. It had a special fixture to hold the rockers, so you could grind the divot out, but maintain the relative geometry.
I seem to remember 0.010" on intakes, 0.020" on exhausts, but you better check that, because I haven't set valves on a slant 6 for almost 30 yrs.
