I must be losing it, I coulda swore I wrote a response to this thread. I currently have a junk yard 4 into 1, and the only difference I saw was it breathes better at a higher rpm. I have a NWOR header in storage that I will run whenever I build another engine, plan on running stainless from header to the tail end at that time too. No cat, neat little sticker under hood says NON CATYLIST, so it's just 2.5" from collector to the tip. I had a Downey header on a parts truck and it was pretty nice, but the NWOR header is the most well built one I've had in my hands and it has that thick flange too.
