Outside Diameter (Small End): 1.055. Spring Rate (lbs/inch): 313 lbs/in. Based around the Lunati Signature Series Valve Springs, the Signature Series Valve Spring Kits are ideal for high stress applications such as professional drag racing and oval track racing. Every retainer, lock, locator and cup was specifically chosen to get the most out of each corresponding Signature Series Spring.The item "Lunati SBC 1.290 Nitride Beehive Valve Spring Kit. 600 Lift 7° 11/32 #75818K2" is in sale since Sunday, April 28, 2019. This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts\Engines & Components\Valves & Parts". The seller is "speedliquidators" and is located in Memphis, Tennessee. This item can be shipped worldwide.