The "Real Deal". I found these along with a few other "GT" parts at an old Porsche Repair shop. The owner actually raced a German Porsche dealer built 914-6 GT during the 70s' and in later years too, he started to remove GT factory parts off the car to replaced them with newer technology to move up in class and be more competitive. Lucky me! ;)

BTW, the port diameter i.d. of the OEM GT headers is 38mm.