I thought I'd restore this old post because I finally got around to restoring the valve covers.
-It took a lot of sanding first. 600, 800, 1000, 1200 grit papers. Then I moved on to the polishes. The drill attachment helped some, but mostly it was elbow grease. My arms ached but eventually I matched the level of polish as the air cleaner.
Now for the ribs- I liked the as-cast look inside the moon air-cleaner ribs, but the interior of the valve covers ribs had a completely different texture (did I mention I can be obsessive?). Texture paint wasn't going to do it, so i went to the hobby shop and bought a medium fine sand - the kind they use for R.R. dioramas. I painted the interior of the ribs with a silver/grey then while second coat was still wet, I covered it with the sand. After nearly drying I brushed out the sand and had a very close match to the air cleaner.
I treated the other valve cover and the air cleaner to the same.
Final step was the decal. I liked what was left of the original decals and thought it'd be fun to update 454 to an accurate 489, as if it was stock Chevy size. I used Testors decal paper (No.9203), as I could run it through my inkjet printer. I created these labels in Photoshop - a much larger scale then what you see here of course.
I applied several thin coats of artists "Fixatif" from Krylon to keep the ink from dissolving.
The decals went on without a hitch.
The biggest difference from original is some details should be white, not clear-over the metal, but I'm happy with the look.
Here you can see how well the valve covers match the air cleaner.
-A lot of effort for a pair of valve covers- but still progress.