PAC Racing Springs’ PAC-1276X is an LS drop-in beehive spring. It offers 150-lbs. @ 1.800, 417-lbs. @ 1.150, a 409 rate, and a max coil bind at 1.070. This drop-in beehive spring provides similar loads and lift capabilities of many 660 lift dual springs, while saving around 30 grams per valve.
For more info: https://www.racingsprings.com/