Grinding, " diesel " noise under valve covers

Take the hold down washers (ie. spacers) out and hit them with a file or grinder about a 10 thou a side. you just want to basically show some new metal on them. This will relieve the rockers from each other and give you some peace of mind. Are the 2 and 4 washers stock? They look a little off to me as well as #3. I just never seen them that shiny.
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Yessir! The hold downs are stock type. Ain't sure where I got em. ( factory, aftermarket, Mancini?) So, for clarification, you are recommending 20 thou between rockers?