Hey Kevin,
Ford had a service part number for Corporate Blue engine paint in quart and 16oz spray, but it was discontinued in 1991. This paint was listed for the ‘66-1980 model years, and the part number never changed. The OE blue engine paint will always have shade differences since these are mass-produced vehicles and engines. Paint batch differences and engines painted at different plants add to the variables. So everyone likely has their favorite version of the 66/ Ford blue.
There again, personal preference. I’ve always used Plasti-Kote #224 with great results. I have used this paint brand on many engine projects over the years and in the shop after the Ford paint was discontinued. This color best matched the blue on the engines I pulled out of salvage yards and shop engine projects. I was informed by a friend who runs a paint supply store that Plasti-Kote was absorbed by Dupi-Color, and many of the Plasti-Kote numbers were discontinued. I hated to hear it was no longer available.
NPD (National Parts Depot) has a reproduction version of Plasti-Kote #224, but it shows out of stock. When I checked for someone on the MCA forum who had similar questions about Ford blue paint last June, it was out of stock then. Supply chain issues, out-of-stock, and back order are the new words for the day now! The NPD part number for their version of Plasti-Kote #224 is AP-EBP. Their part# for Dupli-Color 1606 is AP-EBD, and I’ve heard varied opinions about the color match of this one. NPD also offers a version of PPG 13358, which they have formulated into a spray can and is claimed to be the most authentic blue they have in an aerosol can. If you are painting an engine for a concourse-level vehicle or MCA judging or just want close to OE as possible, you may want to use the PPG 13358. The NPD part # is AP-EB.
https://www.npdlink.com/search/products?search_terms=ford+blue+engine+paint&top_parent=200001&year=