For plating, I try to keep everything as factory stock original as possible in regard to yellow and silver. I am sure on some items I may be incorrect, but it is my best attempt to get things right. I know the earlier Z's had a little more silver items than the later Z's, so not really sure at what times the changes took place. I did notice at the 2019 ZCON, most judges had no idea what was correct so I wasn't marked off for any plating discrepancies. However, Jim Fredericks was there and was able to teach me a bit on some items that were not correct, so I try and learn from those instances.
For the half shafts, since most of the original black paint is usually gone, I typically just strip and clear coat. Sometimes the metal is stained so I paint with flat aluminum and clear or plain aluminum and matte clear. I know they are supposed to be black, but it gets kind of boring under there with everything being black. So, I do take a bit of artistic license on the half shaft, as well as the back of the differential which should also be black.
For the trans case, I hit it with the fiber wheel and clear coat. Wire wheels usually scratch too much. Again, if the housing is pretty stained I will paint with flat aluminum then clear coat.
Also, for the valve cover, I now just clean with steel wool and phosphoric acid (wear gloves and goggles). After the cleaning, I use a little Maguires aluminum polish just as a preservative. I prefer the light bead blast look, but got dinged for that at ZCON. Ideally, I should probably look into vapor blasting for the cover.
Rich