MY bbk swap headers are junk. They are terrible looking, have crimp lines in them from where they were put in the jig to weld them. I had to spend about 3 hours grinding inside all the welds to the "one piece flange" so they would flow good. Overall, bbk has lost a ton of quality over the years. I have a good friend that has bbk swap headers from about 5 or 6 years ago, those are still a very nice piece. He even commented on bad quality of mine. Take that as u will. I have friends that swear by mac......