Has anyone heard of CC978 springs being hit by the rocker arms due to the larger spring diameter? I'm getting a new set of AS 5.3's with those springs and a guy who I consider to be extremely knowledgable says there is a potential for contact.

 

stock rocker arms did on my friends heads... even with longer valve stems...

 

they didn't on my absoute heads. i think you'll be allright.