4-Valve Aircooled Head - How's It Done?

[Quicksilver]

Tuthill is showing off their 11K RPM 911K and Singer has been using a Williams developed 4.0L 4-valve aircooled motor so they obviously figured out how to cool a 4-valve head.
So how are they controlling the heat on a 4-valve head?
Porsche used water cooling on the heads of the 962 and 935 and if they could have figured out how to deal with the heat without adding the complexity of a whole extra cooling system they would have done it.

- So is it improved coatings, improved materials, oil cooling passages, a really really clever new design idea, or what?
It would be nice if the basic technology would filter down to us mortals so you could make an 8000+ RPM 3.2 or 3.4 with 150K mile reliability.

Someone over at Rennlist posted this pic of a bunch of cam towers (the easy part) but there are no pictures of the heads. I wish the picture was a more elevated view so you could see how it mates to the heads.