From what I understand (I'm usually a v8 guy) the pulses should have no barring on weather they fire front to back or side to side, top to bottom, it is the different cylinders firing in the different header pipes to help with the scavenging effect, not just to reduce noise. I hold little vitality to any test done in the 70's or earlier, so much has changes that these old rules do not apply any more, remember the old 30/30 cams?? Lots of duration little lift, because of poor flowing heads, cams and heads have come soooooo far that you cannot compare them anymore. What is faster a 2006 Z06or a 70 LS-6??? Both have about 450HP. Now back to the six surely a crossover would not defeat the purpose of adding the header, after all you have SO much added surface area of pipe, increased flow, so with adding flow of more surface area adding a crossover is not going to defeat it and bring you back to "stock" performance, just can't happen so that throws you theory about defeating the purpose of installing headers.
Do disrespect in my post is intended, if I offend I apologise.
Jon
