The egr supply tube can be plugged with a straight thread metric plug, I find em at hydraulic shops. The egr system will now have to be properly disabled though.... otherwise you'll end up with a check engine light and pinging under load.
Thats for the egr supply. The threads are terrible even when you do find a plug for it. I found a plug at a hydraulic shop. Ive been round and round with bbk tech about these 40070 headers btw....