I guess this goes in this area.
I'm looking at buying an aluminum valve cover for my 250. I'm thinking of having it polished and clear anodized. Is there any reason this would not be a good idea?
No reason whatsoever that I can think of. The only thing to be aware of is what valve gear you're using. On my 250, I used Crower steel roller rockers, and had a Mercruiser aluminum valve cover I was planning to use. The plan didn't work out, because the Crower rockers (with the locking adjusters) are taller than stock Chevy rockers, so the Mercruiser valve cover wasn't usable after all. I had to get one of Tom Lowe's aluminum valve covers to have enough clearance for the Crower rockers. I suspect that other makes of roller rockers are similar, at least the full roller rockers that have both roller bearings and roller tips. The roller tip rockers that use a standard type rocker ball would probably be fine as far as clearance goes. With full roller rockers, Tom Lowe's aluminum covers are definitely the hot setup.
But if you're using stock rocker arms, you should be able to use any aluminum valve cover you want. Polishing it and clear coating it might possibly have some minor effect, but it would be so small that you'd never be able to notice it. On the plus side, a polished aluminum valve cover really looks good.
