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. This is a drop-in kit for LS9 heads. The kit includes dual polished springs, locks, and your choice of: • Titanium or Chromoly Steel Retainers • Locators for Stock or Bronze Guides • Valve Seals Spring specs are as follows: • 155 lbs @ 1.780" • 380 lbs @ 1.180" • 400 lbs @ 1.130 • Coil bind @ 1.070"