Finally get to pretend I am one of the cool kids - Holley kit swap

So you are running the TTI kit? And similar clearances, i honestly think adjusting the header would be the easiest option for him, as looks like could hug the block tighter
Yeah, it's an old setup though. I did my swap with an 06 5.7 the better part of 10+ years ago, so TTI was about the only option out there aside from stock manifolds. Can't complain too much though, it all bolted in fine and seem to fit okay. Definitely tight in a few places like the steering box and torsion bar, but it all clears as far as I'm aware. The coating on mine went bad pretty quick though. They were supposedly ceramic coated, but they have flaked and pitted pretty bad on the bottom end of the car.