I've tried all the spray can paints that claim to be Corporate blue, but they were not a good match to my original Corp blue engine paint. It was either too light of a blue, or too dark, and not the right shade of blue. So, I didn't use them.
As Canamman said earlier, the original PPG code number for 77-up Corporate blue engine color is 15159. If you want to have some mixed for use with a spray gun, you could check with your local PPG auto paint supply store and see if they can mix it. They might be able to.
At the time I wanted some engine paint a few years ago, I didn't know the original Corporate blue PPG number. So I had some paint matched to my original valve covers that still had good original paint on them. Below are pics of that paint. The paint matched to a Tuscan Blue, PPG #16513, mixed in Shop-line JAU single stage acrylic urethane. Shop-Line is PPG's economical urethane paint. That's the paint on my engine below. So, if they can't mix 15159, I know they can mix this color.
Also, as Canamman said, the Dupli-color spray can paint that is the best match for Corp blue is actually a Chrysler green, #DE1619. It's not really green. It's more blue with a very slight greenish tinge. It matches very well to the color on my engine seen below, and as seen in the pictures in Bob's car that Canamman posted.
So, if I was going to have some paint mixed, I'd try to get the PPG 15159 mixed. If that's not possible, I'd use the PPG 16513 that I had matched, since I'm happy with it. Or if just using rattle can paint, I'd use the Dupli-color DE1619.
002 by
grand73am, on Flickr
004 by
grand73am, on Flickr