Alright well, I got it all out and cleared the threads. The threads are a little loser than the others, but it's not bad. I think I'm gonna have to disconnect the steering shaft in order to put the head shield on though.
Also, since my plan is to put on duals, which isn't strictly smog legal, I'm bolting everything together with these nice stainless band clamps that I got from Summit. That way if a smog shop doesn't like it, I can fairly easily switch back to single. I got the Magnaflow 36006 cat from them too, and I'm hoping to be able to just clamp it in so that when I switch to duals I can just unclamp and reclamp. I test fitted it and it seems really solid, and if I throw some high temp silicon in there it ought to seal really well too. What do you guys think?