Dougs installation problems on '74 Duster

SO, I bought the Dougs D453 headers for my '74 Duster. The applications only list '70-'72 dusters for them, but I was told by a couple members on here that they know for sure that they will fit a '74, so I got them. I don't remember who it was that told me that, or I would PM them for help. Has anyone done it, and if so, how??? Thanks in advance.