It was war-time. The Top Secret nature of the project was important to keep from the enemy. Afterward, It was reduced to confidential.
It matters not. The issue is that it has been widely accepted by the top researchers that valve temperature follows CHT and ICP and not EGT. The temp of combustion skyrockets. The ICP skyrockets. The CHT can go up 2 degrees per second. There has been confirming evidence posted as in detonation and preignition that this is true.
If one insists that EGT is a factor, please reconcile the preignition DATA that Jabba posted. We have a bucket full of these files and in every case, it is the same. Falling EGT, rapidly rising CHT. How can one with intellectual honesty suggest that during pre-ignition that the valve is running cooler because the EGT is falling?
This is not unlike those who insist that lead lubricates the valves. That's a religious fervor to support the unsupported.