"sourced from a Dodge Lancer station wagon…the turquoise paint really dressed up the cast iron block"
Fail! That's an aluminum block motor they took out of that '61 Lancer wagon. Not a word about that in the article, even though it would've required special parts (head gasket, rear main seal parts) to build up. Even though it would've been exactly the kind of cool-old-car stuff Hagerty customers (and potential customers) would eat up with a fork and spoon.
My biggest question is exactly what paint they used for the head and tinware on that aluminum engine. It looks like a 10/10 match for the factory '60-'61 engine paint as described here. Who knows, maybe they read that thread and cadged the paint code from page 3 of it.