Headers for 1966 Barracuda 273 Commando formula S

Yeah, I'm not sure you have a lot of options. I don't think TTI makes any for narrow bodies. I don't know if Doug's or Hooker even make them, and most people wind up hating those by the time they smash them up enough to fit, even on a 67-69. I know the Spitfire tri-Y headers fit, but those are rarer than rare. Block huggers may not offer any improvement over the factory exhaust — it is supposed to be pretty efficient. I have a Commando in my 67. After the OEM system rusted out I went with dual pipes, but it's a real tight fit on the right side and I can't say that I noticed any performance improvement, it just changed the sound.