This simply is not a concern. What you are asking about would be for an ultimate high rpm endurance engine.
First off, you would be using the wrong head. These are production heads and you will find that there is a special casting for the factory comp cars called a GT40 head. Even so, the era in which those cars raced the technology that you speak of hand not yet arrived. Even if it had, the design of that head being based off of a production design would have been as Ferrari stated, for "an irrigation engine".
The best that you can do, and all that you need to do is change out the complete cast iron valve guide for the current version of bronze that is currently used in aftermarket aluminum heads like Edelbrock, AFR, or take your pick.
There are several variations of "positive valve guide seals" available and all are just as good as the other. I still use the Teflon ones but they are available in viton and other materials. Most exist simply from preferential engineering specifications from one of the major car manufacturers. Any will do the job.
They are all minimum in size and usually fit right onto the already precut bronze valve guides but if you want to stay with the original integral iron guides cast into the head, all you do is a very simple and easy cutting/machining down of the guide with an inexpensive carbide bit supplied by the seal manufacturer. All you need is a competent drill and even an 18volt Ryobi will do the job.
You also need to consider which valves you are using. If you are switching to current stainless, they are all a much higher quality alloy then ever existed back then in "the day".
I understand the concern that prompted the question but it really is a good example of way over engineering a project. All you are attempting to do is put lipstick on a pig. Be my guest but it's still just a pig.

Have you ever seen lipstick on a pig? Yuck!
