I'm sure the manifolds were on it when painted. I don't think the breather cap was painted, so it would be semi gloss black. krylon is very close, unless you think you need a 2 part paint.
I say using krylon with good prep and primer is 10 or more times better than what the factory used.
235's in trucks were mostly grey, maybe a different plant used blue don't know. They were build all over the us so it could be a use what you have deal I don't know. I don't think all the bellhousings on V8's were painted. I do think the 6's were.
If you had a truck that had a dealer replaced engine for some reason, it could be built up from part off the original or with new off the shelf parts, then you would have a mix match of parts colors, like black oil pan, damper etc. I don't think its too far off stock doing that sort of thing it looks nice too.
