Herb, try looking for a Mercruiser valve cover on eBay. They're aluminum, but are the same height as the sheet metal Chevy covers. Just make sure that when you find one that it has the second hole for the PCV valve. They come both with and without PCV valve holes, and if you go to the Marine section of eBay they usually aren't too horribly expensive. Also, another thing you might want to do if you use the sheet metal cover is to get some valve cover hold downs which will help spread out the clamping force and lessen the chance of bending the cover when you bolt it down. Most of them are for V-8's, but a few minutes work with a Dremel and they'll fit fine on your 6 cyl cover. You can usually find them at Auto Zone, NAPA, or Checker/Schucks/Kragen stores, and if you don't want to do that, a 1/4" washer will do in a pinch. I like stainless steel, but it really doesn't matter that much if they're stainless or not.
