mercruiser valve cover for chevy 250?

I've heard that these are aluminum finned valve cover and will work on my 250. Anyone have a pic? What would I expect to pay for one?

 

There are also alm side covers, I have been watching for a set on Ebay, they show up every couple months. I always come in 2nd bidding.
old spoke

 

125

 

one here on the Hamb for sale now
http://www.jalopyjournal.com/forum/threads/mercruiser-valve-cover-for-chevy-194-250-292.1021569/

 

I have one on my 250. And it isn't a Mercruiser engine. It's kind of finned, but not in a Cal Custom way.