Though Kerrdogg did a simple test showing more pressurized air coming out the back half of the intake, we still have to be at least a little humble and considered outlier factors.
It wasn't installed on the heads. We all know there would be a difference "installed" on a running engine. I'm sure Ford did plenty of computer modeling coming up with this intake and I've always and still do feel it is a great design. IF....IF #6 gets more airflow by a significant amount....go out and pull all your spark plugs. Now look at the heat mark on the ground strap. #6 and #3 should, theoretically be further down the ground strap from where the spark occurs. This intake was obviously not designed for FI or distribution with FI in mind...go look at a 3.5 turbo intake.....
#6 could have been tighter in the bore to begin with (but it's obvious it did get hot and expand faster than the bore did due to the scuff/wiping out of the whole ring land all the way down to the skirt)
Overall, I think it's an excellently designed oem intake for near stock bolt on cars from my experience with induction, porting, and design. Now when you start changing cams, you should still be fine with porting (like if I reshape the runners more, more material removed while having to epoxy the runners) (Don't worry about runner length and paying thousands for and intake to optimize for low single digits NA just yet).