Crane Cams 99838-16 1.465" Dual Valve Spring, (Set of 16) Average spring rate is 438 pounds per inch Outside diameter of the outer spring is 1.465 Backed by Crane's 1 year Warranty Policy under normal use Inside diameter of the inner spring is 0.807 and outer spring is 1.091 Springs are selectively magnaflux inspected and checked for tension