IMO the engine block, oil pan, and heads need to be Ford Blue, to keep the theme of the Blue Oval. There is a lighter & darker color Ford Blue.
The front dress and top dress accessories can be aluminum, or polished, or whatever color you like. When the engine is viewed from the bottom-up, there's no mistaking the Ford Blue heart of the classic.
And NO oil leaks! If/when it gets a leak, fix it, LOL. There isn't much more gross than having your engine puke oil all over the goodies underneath it.
For a carb engine I like the factory Ford Racing air cleaner housing to add a little bling