Joe,
All I know so far is that Marv had a BH owner in AZ take his bike to the fabricator (we met the BH owner @ Osage) and they developed a set of bolt on headers for the two wheelers. They used the 'Tri-Y' configuration instead of the equal 4 tube design like Sanderson did for Adrian. The theory behind this (not new technology) is to match cylinders that fire 180 degrees apart to scavenge exhaust better. Obviously on most vehicles, space doesn't allow this to be done @100%, but they have developed a system that gets pretty close.
Actually, I had researched this style of headers for my motorhome through Thorley.........big increases in low to mid range, no detriment in the upper rpm band. Thorleys site and several others have dyno specs that say 'tri-y' style headers typically gain between 15 & 18% in HP & torque.............for a motorhome that is a bunch.
The headers are coated and plated, saw a set on a big at Osage, from a distance you can't even tell their different. Stock heat shields are adapted to fit and look pretty good.......did not hear them yet, but I doubt they will have the very distinctive sound that Adrians' have........if you have not heard Adrians' small block with his headers, you are missing something
I believe Marv said they were $1500 complete............bolt on, reinstall the heat shield, drive away. My goal is to continue to gain HP, but not affect the relliability of the engine..........i.e. NOS, headers, ignition, etc.....
so I can just get on and go every time I hit the starter..........
He had a few sets delivered this week and they were going to the ceramic and chrome shop. I'm going to stop by there tonight on my way home and should have more info Monday for ya.
You can look for Dougs or Headmans sites and they both have info on this configuration.
Tim