I didn't know they were THAT bad in stock form.
I went looking for that sort of info when I built my engine since I never got to flow the head before any work was done to it/ but so did after the work that was done to it, was done.
On that note the bench that mine was tested on, has moved to "unreachable" distance from here recently.
I do appreciate the opportunity to have had one done /if only for curiosity.