Cylinder Head/Flange/Headers Question

I bought a 1973 Dodge Dart Sport, and for the life of me I can't find out what cylinder head is on this engine. I heard it was a 360 build, but there is some type of sub flange between the headers and the cylinder head! I've never seen this and is it necessary. Can I take it off. Only this header will fit that bolt patter of the flange, I have no idea what the bolt pattern for the exhaust looks like under the flange. I'm also having trouble finding a header that will fit those flanges. Don't know the make of the headers either. Yea, I know i'm lost here, but if you guys have any information that could help me I would appreciate it. I've included a picture hope it shows up!

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