You may have to undo the bolts that hold it to the side of the block. Once you do that, use some force and pull it away from the header just enough to fit the header in place and then work the EGR pipe (metal pipe) back into place. If that doesn't work, call Joe @ pacesetter. Give him a hassle
I'm still waiting on him to fix my header. Either he fixes it or he gives me my money back, I'm not about to go through 19 hours of labor again for a stupid header.
Good luck, and don't over tighten the header manifold bolts. I did that on mine and one came out stripped... just make it slightly snug or use the torque manual or whatever they use for torque specs.