I currently have a AMC 360 V8. I had been running stock exhaust manifolds. I recently ordered Edelbrocks ceramic coated headers that were supposed to be a direct replacement. I had a custom exhaust fit to the original manifolds, so in essence, they should fit the direct replacements headers. Passenger side lines up and has dounut at flange, driver side does not line up. Header flange (at collector) is way forward and has the need for a dounut at the flange whereas the original manifold was cast to recieve the flared end of the exhaust pipe at the exhaust flange. I went to Edelbrocks website and for this engine, the part number for the ceramic coated headers was the same???? I am confused