I have no idea if your red pipe will impact your decision, since I have no idea if that mounts to the head or not. (If it does, I think adapters are available but that adds to the $).
However, the simple answer is: girdled. It is meant to take stress off of a known weak spot on the 61x cylinders. Now, of course there is debate about the effectiveness of this, and who has the best girdle bolt / stud design, but that is the design intent.