To duplicate the original finish with out paint, sand as if to polish but only down to 400 grit, then polish until the finish is uniform, and all sanding marks are gone-not to a mirror, but to a smooth finish. That will be the approximate finish of the inside of the original mold.

Will

Used the Ford blue on mine. Came out pretty good.

Personally, I think the Ford Blue is too blue. I purchased a can labeled Ford Blue put it on the old alternator bracket, then compared it to a new one already painted from Nissan. The new Nissan bracket has a greater tint of green.

I took the new bracket to the paint store & had a pint matched for about $40 last year. My camera is old but I think you can see the difference in the two. The second pic is my in-progress engine bay with a powdercoated valve cover.

Here are a few pictures of my cam cover as it is after bead blasting and several coats of clear coat. (I also contrasted the indents with high temp black and then polished the lands and 'nissan ohc' with progressively finer sand paper down to crocus cloth prior to the clear coat.) Sorry I did not post them with the first reply. These get the message across much better than trying to describe in writing. As for engine color, I have tried "old Ford blue" on a couple parts I have on the bench. The results are okay, perhaps a shade too blue for a purist.