[99LeCouch]

That's the most coherent explanation of exhaust sizing I've heard! That makes a lot of sense!

Throw in a term genuinely used for another engine application and there's an instant recipe for confusion.

Isaac, on our cars a ported and polished lower intake manifold is supposed to help out quite a bit all over the rev range. I have one I'm installing in a month. Seeing how I'll be doing a lot of driving this fall and winter, I'll have results to report back.

Some cars come from the factory with adequate exhausts, but junk it up with a restrictive muffler. Often changing the muffler to a less-restrictive one is as good as changing the entire exhaust system. Again, you don't want to over- do the free-flow.