those are not headers, they are cast iron manifolds. They are from a Dodge Dart year is probably late 60s, if you look close you should find a casting date on them. the casting number 27xxxxx is from the late 60s.
Small block Mopar.......273 or 318 from 1964 thru 1969.......or so, Mopar used up parts until they ran out their last year in the next model year often.......the gold engine in the pic is a 318, the size is cast in the drivers side of the block and visible in the pic. I had a 69 Valiant with a 273 that had those manifolds. MM