+ .050" installed height. Increases installed height, allowing the use of a higher lift camshaft without the need for removing/cutting valve spring seat pockets/depths. Keeps the valve spring pressure in the proper open height specifications. These valve spring top collars (Upper valve spring retainers) come in a 8-pack and are compatible with stock, Screamin' Eagle and Feuling's 993530 and 588022 Beehive valve spring kits. As strong as the steel but much lighter to help prevent valve float when you turn on the heat. Custom replacement for the stock 18100045 valve spring top collars.