What is the absolutely correct blue engine paint color for a 74 Duster?

As others have said, the tones/hues of Mopar Blue probably vary from manufacturer to manufacturer. I had an old rattle can of Mopar blue I used about 15 years later and noticed it was brighter than what I had sprayed many years earlier. Point is, the heat, chemicals, engine degreaser and road grime over the years also fades the paint on the engine.