I'm in the planning stage of building headers for my 263, and had originally planned on building one for the center four cylinders and another for 1-2-7-8. This would put alternate firing cylinders into each header. However, I had an interesting thought just a bit ago as I was sitting on the throne. How about a pair of headers where four consecutive firing cylinders dump into one header, and then the other four dump into the second header. There would still be scavenging for at least three of the four cylinders, and the header would be a lot easier to make (firing order is 1-6-2-5-8-3-7-4), so exhaust ports 1 and 2 could be paired as well as 5 and 6, resulting in a pair of tri-Y's. If nothing else, it would really have a funky sound at idle, with four consecutive exhaust pulses out one pipe, then it "going to sleep" for a bit while the next four exhaust pulses came out the other. Thoughts?
You might take a look mercedes W196 & 300SLR from the early fifties, they were one of the last high performance straight eight engines and they were just starting to get their heads around tuned exhausts
Here's how we did it on a big Buick way back when. I don't know if the firing orders are the same on the big ones; we were trying to make them 180 degree.
Yes, those would be 180 degree. Mine need to be tucked in a little tighter. This is a nice job, but there's no attention paid to firing order in this construction, It is simply the front four into one header and the back four into another. But basically that's what's done with 99.5% of the V8's today. one side of the motor into each header, which works but isn't optimal.
My thought is you should figure out that spaghetti before I get to that point on my I8 project! I also think the four and four firing will sound B/A! It might give it a cool old airplane kind of sound or like two engines in one car.
The Jalopy Journal
