BBK pretty much sucks. I had a problem with the weld not going all the way around the flange when I bought my BBK LT's, there was actually a gap. Needless to say I was pissed off, brand new headers that came from the factory leaking. This was the second set of BBK headers I'd bought from Summit that had a problem. The first set I bought, shorty unequals, came from the factory tweaked, 2 of the flanges were bent slightly, so they never sealed correctly. Anyway I called Summit and adamantly made my case. I have to say that Summit was very good about it, I was ready to buy a set of Bassani's or anybody elses headers. The guy at Summit ended up sending me a set of Ceramic Coated BBK LT's for the price of the chrome, which was nice.
I've never seen any of the welds on the BBK headers I've had that didn't need to be ground down.
After I thoroughly checked the new LT's I received, I ground the welds down inside the flanges, just enough to even them out and open them up a little. Haven't had any problems.
FWIW, I ended up writing a letter to BBK about the problems that I'd had with their headers and told them the only reason I am still using their product is because Summit is so good about their customer service. I never recieved any response from BBK, and because of that those headers are the last piece of BBK equipment I'll ever buy.