This is our hardened valve spring locator cup designed specifically to suit the "Green" valve springs we sell.  The cup performs two important functions, first it keeps the hardened valve spring from wearing into the soft cast iron of the cylinder head and secondly it provides positive location of the valve spring relative to the valve stem.
Depending on the final valve lift, it may be optimal to machine the cylinder head to create a recessed pocket for these spring cups to sit in.  We can machine your head for you, at additional cost, if you wish to recess the cups into the head. 
Priced individually, sold only in sets of 8 or 12.
Wholesale pricing available for quantities over 60.