With raised port exhaust heads you have the same issue with fitment as a tall deck BBC does in clearing everything. You raised your ports 0.300" and the Tall Deck truck block raises them 0.400". This brings them closer to the steering gear box and gets in the way of your clutch linkage (which is usually fixed by going to a hydraulic clutch out of a third gen Camaro). The hydraulic clutch conversion also requires reinforcing the firewall, in addition to new parts.
I gave up on off the shelf headers because they don't fit most of the time. I use a stainless steel variant of this kit and take them to my muffler shop to be TIG welded (I am not that good and trying to get a torch in a small area with my big paws is difficult).
The Kit I use: