I am reconditioning a set of BBC truck heads and each spring (ex and int) has a thing underneath it that appears to be a valve rotator? Not sure, never seen one. They are about 1.8 to 1.4 inch thick and consist of two cups basically that spin against each other (like a turn table).

I want to replace the springs and am wondering if these are necessary to keep in there or if it would hurt to leave them there? My cam lift specs are .515/.530. Let me know if you need more info. Thanks. I plan on using a single spring w/damper.