The BTR Platinum Spring Kit would be inducted into the LS Aftermarket Hall of Fame if such a thing existed. Whether you’re putting together a daily driver with a mild cam, a 600 hp N/A stroker, or a turbocharged 1000 hp brawler, our Platinum Spring Kit will make sure your valves are right where your cam wants them to be at all times. They are designed to be used with stock rocker arms. If you go the roller rocker route, see part # SK002. This is a drop-in kit for 15° LS heads. It will also work with LS7 heads when used with a .045” shim (Part numbers SS015 +SS030). This kit will not fit LS9 engines. See part # SK006 for LS9 heads. The kit includes dual polished springs, locks, and Titanium Steel Retainers •Locators for Stock Valve Seals Spring specs are as follows: •155 lbs @ 1.780" •380 lbs @ 1.180" •400 lbs @ 1.130 •Coil bind @ 1.070"