I met John Kaase in 2010 at an Engineering Seminar. He explained that on a Race/Hi- Perf. engine the header primary should be 10% larger than the exhaust valve and no bigger.  This would make my primary's at nearly 2 inches inches in diameter.(2"  primary tube headers) Exhaust velocity is critical for  pressure wave tuning. It's good to hear the X or H pipe systems are on the right track. I think I am going with Dyno-Max Ultra flos. All in all a lot of expensive and time consuming testing which most Rodders don't have access to. When the time comes I will have unlimited chassis dyno tuning,(at my Alma mater). SuperFlow Chassis dyno, I would love to see the latest Nascar exhaust tech, they have what amounts to the closest exhaust system,(V-8, cam in block, same type of chassis, under carriage design, nearly same length),  as our Muscle cars and they are paid to extract as much power as the rules allow. I do know that at some race/show car with racecars I see,   they hide the Collectors,,as the article mentioned,,there is a lot of tuning on the table with Collector size & shape. Interesting what he said about the tailpipe after the muffler. Didn't you try to mod your Vettes tail pipes Dave,,to no avail ? Too many curves! 

  Erotic,,I mean  exotic exhaust! 
