[markjohnson]

I'm a big fan of exhaust scavenging theory and have used Belanger Tri-Y's (or 4-2-1) on my Z06. I've always liked Tri-Y headers and they're supposed to be superior to conventional headers, especially street-driven cars, but they're hard to find because they're more time-consuming (more expensive to manufacture). Doug Thorley or Belanger Bros. manufacture them but mostly for small blocks. I have a set of the Flowmaster Scavenger collectors that I'm going to use on my next BBC project. The Flowmaster collectors basically convert a typical 4-into-1 header into a Tri-Y header by separating the exhaust pulses away from each other and are great for building mid-range . . . .you know, right where the tach likes to drop to after every gear change! Anyway, you have to join the proper cylinders together for them to function properly= 1 and 5, 3 and 7, 2 and 4, 6 and 8. Most of the time with the Flowmaster collectors, you need to swap a primary tube or two with each other so you can can pair up the correct cylinders into the scavenger collectors. One more quick note . . . if you happen to have one of those 4-7 swap camshafts that are so popular these days, then you need to do different cylinder pairings than the ones I listed above.