I built a second header for my car, this time in stainless.

Dude. I don't know why you're so pissed about this. You are actively fighting over the difference between clinical definition and actual real life performance. Clinical definition, you win, huzzah. You're right. But performance says that even though you can have a header with different length pipes, and that will still be defined as a header, you should never do it because it has a shit load of problems. What I copied from Jegs above boils down to Equal Length = Good. Non Equal Length = kind of shit with lots of problems, aka: you should never do this. That is all I was trying to say at the time when everyone sent me to down vote hell. At the time I did think that was the clinical definition of what a header was, I thought it HAD to have equal length pipes. Because I've never seen a professionally made set of headers with non-equal length pipes before. Maybe they exist, idk why you'd want them, but maybe that's a thing out there somewhere and someone could send me a link to and then explain to me why you would ever want non Equal Length tubes. What is actually the truth is that a header just has to have a separate exhaust pipe for each cylinder leading down to the collector. They don't have to be equal length, but they always should be.