Someone more into original stuff can fine tune my estimate but I believe there are nine different levels of black gloss originally used under the hood. Pontiac listed them as 60% gloss, 80% gloss, and so on with the higher percentage going towards a higher gloss finish. Someone, somewhere, has a list but I don't.
My favorite go-to spray can is also the Rust-oleum satin. It's a pretty much one-size-fits-all approach. Then I'll go back and take things like the finger guard, air cleaner base, and a few other things and make them a higher gloss just so the whole engine bay doesn't disappear into a black mist. A higher gloss stays cleaner but also must be cleaned more often to look good so rather a push, and personally I find high gloss inner fenders or radiator supports a distraction.
My favorite go-to spray can is also the Rust-oleum satin. It's a pretty much one-size-fits-all approach. Then I'll go back and take things like the finger guard, air cleaner base, and a few other things and make them a higher gloss just so the whole engine bay doesn't disappear into a black mist. A higher gloss stays cleaner but also must be cleaned more often to look good so rather a push, and personally I find high gloss inner fenders or radiator supports a distraction.
