Quote Originally Posted by GTPpower View Post
Settle down man. I'm just trying to help bring some relevance to your test.

Look at an exhaust port on a head. It's in the shape of a D. Which roughly matches the port on a stock exhaust manifold. The powerlog is a circle, and by it diameter alone, it will easily outflow the stock manifold. Or a ported manifold. If you don't use a head, you are completely removing the portion of exhaust that initiates the speed, direction, and other flow characteristics while the exhaust gasses are in their most expanded state. Your test would be valid if you were deciding which to use for an underground sprinkler distribution manifold, but it means very little on an operating motor.

Also, I hate headers. From all the cars I've had, they've been huge headaches for the little gain (if any) they offer. I never recommend then anymore unless you are trying to run faster than 12's. The last car I built, the 04 in my sig, made 320whp all day long through stock manifolds, E85, 3.4 pulley, and a very conservative tune. It could have easily made more, but the fuel pump couldn't keep up.
I was about to respond to this exactly what you said, but you made the point very well. Without bolting it to the head I think the numbers are useless. I'll go unbolt my gto headers and get those numbers too, that should correlate well to the 3800 engine. If I want more flow I'll go get some 4" PVC pipe, that should flow a lot more. I'm not trying to be mean but that seems to be the testing method. Even when flowing heads you put a pipe to simulate the cylinder or exhaust. It's not "which one flows more air" but which one will flow more air out if the head. GTPower was just trying to show you why doing it that way is a waste of time and why the results couldn't be used much less weren't even close to scientific.