What Fits Under Factory Valve Covers?

Yeah but if stock doesn't fit I'm okay with a close look alike, especially if its DC stuff.

I had already contemplated the idea of hacking up some stockers and adding a half inch of sheet metal. Only problem is when chroming stuff the finish needs to be like your previous avatars that showcased some of my better work. Doctor assisted, of course.
I saw some cover spacers for big blocks on ebay------------