Oh My!
i understand how equal length headers tuned for a specific engine will keep
each bank of 4 identical cylinders effectively scavenged and maximize power.
...and i understand that you think joining them will make even more power!
I don't think it. I know it. Because it's proven. Over and over again. By many different people, race teams, performance shops, etc. Using the opposite bank of cylinder's to promote and increase the scavenging effect is well documented. And it has been explained here how it works several times.
If you'd like to tell me what part you aren't getting, I will honestly try to explain it for you. I can get as technical as you like if it will help you understand. But I honestly think you aren't actually interested in learning about it, cause you've refused to listen to or understand all the explaining we've done here.