I have a stainless steel flange that you would need to install a hks 40 mm gate this is the inlet flange that you would weld to the headers. It is not the flange with the seat on it. $20 paid $100 for it due to the vendor shipping it via ups to me. thanks
http://www3.sympatico.ca/norbz/flange.JPG
http://www3.sympatico.ca/norbz/flange.JPG