I'd have to see them all parked side by side, but I remember AMC big bad blue, Fords grabber blue, and Petty blue (by whatever Mopar name) all looked the same to me.
1972/1973 B3 blue is very much similar in color as Ford Grabber blue and AMC Big Bad blue. I'm sure they're probably slightly different in formula, but if you look at the picture of the floorboard of my Challenger you can see that's about the color. Non metallic light blue. It is also pretty much the same as all of the "Petty" blue cars I've seen in person, but as I corrected myself earlier "petty" blue means different things to different people, Petty enterprises supposedly has a copyright on it so the guys that do Petty car clones apparently go to them. And unless I've missed something, you won't find a factory paint chip called Petty blue.