This is a great article and very timely considering the prominence of the recent film, Ford v Ferrari.
In my discussions with "survivors of the program", it agrees with this written interview that the Lemans engines were just not capable of over 7,000 rpm operation. The key factor being that was the ultimate rpm capability of the valve springs available at that time.
I personally never take feature films as absolutely correct on facts or details but the scene(s) in which Miles goes to 8,000 rpms seems to be "a fiction of poetic license"?
This written interview of the head engineer overseeing "the beast" just confirms what I was told in my own personal"interviews".
I also don't know how the films writers were able to resist inserting the comment made by Ferrari himself, "beaten by an 'Industrial Irrigation Engine' "?