SLP Retainer, Titanium Valve-Spring LS1/LS6/LS2 use w/#53003 (set of 16) The perfect match for our LS1/LS6/LS2 performance valve springs, these new custom-designed titanium valve-spring retainers are built to withstand both increased spring pressures and higher-than-stock RPM. At only 9.5 grams each, they're a full 2.5 grams lighter than the OEM retainers. Compatible with stock valves.