Not sure if anyone will respond to this since this thread is old.....but, I have a 73 Duster 340 with 4 speed, I was looking a going with doug's headers. I'm just trying to find out if they will clear the z-bar. I'm currently running the 340 Hi- po manifolds from the aar an t/a 340, with tti down pipes. I had to ding the driver's side down pipe and shim the trans mount to clear the pitman arm. I'm just trying to find a header that I can install with out modifications. I don't want to do any hacking smashing bending prying, or cutting and modifying the z-bar. Any advice or first hand experience or knowledge appreciated.