Has anyone ever heard of custom "Y" type headers that connect cyls that are opposites; fireing order-wise?

By that I mean "Y" cyls 1 to 6, 8 to 5, 4 to 7, and 3 to 2.

Then, a little further down, "Y" together the 1/6 pipe to the 4/7 pipe, and "Y" together the 2/3 pipe to the 5/8 pipe.

Seems like that set-up would provide the smoothest, most efficient flow since the exhaust pulses would all be evenly spaced and would tend to assist each other at scavanging exhaust.

 

Those are "Tri-Y" headers... those are great for the street because they make lots of low end grunt compared to the usual 4-into-1 headers.

 

The TRI-Y headers are a compromise of the original idea.
They don't cross over from one side to the other 4 times like mine would. They get close to connecting opposite cyls, but they are still out of sync by one cyl.
This explains it better:

http://www.thorleyheaders.com/tech_basics_triy.html

They are what gave me the idea to begin with.