I thought I put all that in my signature
Ideally, it's the first thing you type into the text of the first post. If it's in the title, senile old folks like me forget between the time we read the title then click on the thread link, and start reading the first post. If it's in the signature, or your user info, there's no guarantee that the vehicle you're talking about is the one you've described when you filled-out that part of the forum personalization.
In other words, I could put my '88 K1500 in a signature, but maybe I'm posting about my '97 K2500. Or maybe I'm posting about a friend's vehicle I happen to be stuck working on.
When the vehicle you're asking about is clearly mentioned first-thing in the main part of the first post, there's no confusion.
Weld a bung into the header tube, screw a fitting into the bung, and install the EGR tube onto the fitting. Or buy headers with the correct bung already installed.
Use the same fitting GM used to connect the tube to the exhaust manifold.
Reinstall the same number of catalysts the vehicle was born with, in the same location as originals. But I would buy "Federal compliant" aftermarket high-flow cat(s) with larger inlet/outlet tubes rather than OEM-level (California compliant) expensive cat(s).
For the record, depending on the "conversion" kit you used, you probably have "disc brakes" not "disc breaks"; although if this is a cheap-junk flat-bracket disc conversion, you may wind up with both--disc brakes that break.
