Kinda looks like a Nailhead to me.
Your right Dave the exhaust ports are not a nailhead they do look more like an Olds or Pontiac I was looking at the gasket surface by expanding the picture.You know, I went back and looked, the valve cover seems level like the nailhead, but the exhaust port and pipe grouping is wrong for a nail. Exhaust grouping looks more like an Olds or maybe Pontiac. Picture is just fuzzy enough thats its hard to identify.
Who is sneaking around the corner?