Probably made in China. That being said I've run similar inexpensive designs from China on some LS engines and they've panned out to be pretty good. BUT take this into consideration when you're shopping...
I did find out that most of the sets on eBay being sold as "stainless steel" were a lower grade of SS that could still rust a little. They were also only stainless tubes that were welded to a chromed regular steel flange! I also found out through a little industrial espionage
that these headers were actually available from China in higher grade stainless for the tubes and the flange AND available with collectors included. Unfortunately, I couldn't find any retailers who would confirm that their sets were complete SS and what grade they were.
