Hooker header poor design
Years ago, I helped my buddy install a set of Hookers on his 360 Mustang.
We noticed the lower side of the ports were blocked, this was due to the tight engine bay.
He called Hooker, they said it was fine & the exhaust flowed mostly out of the top of the port.
Yea, right.
We still installed them, what else are you going to do?