We're giving my 67 a frame off restoration and we're going to reassemble soon. Can anyone tell me what items were plated with what? I want her to look original and we have a friend that does plating. Thanks in advance!
GM used in addition to the obvious Chromium plating, the metals Tin, Cadmium, Nickel, and Zinc for plating. GM used black oxide on all bare steel sheet metal after it was formed, which is cheaper than paint and does a better job of rust protecting the parts (though it fails as soon as the oxide is scratched off).
I am sure I missed a few. You can buy every OEM bolt that was used by GM, with brand new coatings on them, from many vendors; to build a white glove concurs correct museum piece. I wouldn't try and replate them with an Eastwood kit or anything.
I do not like reusing fasteners anyway as they are only good for four to five torque applications before the threads start to deform. That is why in every engine I build I replace every nut, bolt or stud in the engine with new ones from ARP.
It is hard to find specs for your 67 Impala but the Camaro and Corvette guys have it documented very well. Generally brackets, trim, bolts, suspension parts, and such are plated the same between models (not always true) so you can used them as guidance. I finishing up on my 67 SS also and had the same questions.