These Beehive Valve Springs from GM Performance are replacements for our GM 604 Crate engine. With a .570" maximum lift, they allow big block engines to turn more RPM too. The unique Beehive shape handles valve train stress more efficiently to eliminate damaging harmonics and increases high RPM horsepower and durability. The oval/multi-arc wire shape places the maximum area of the wire at the point of highest stress to handle valve train stress more efficiently and allow better heat dissipation for longer life. Specs Sold in Quantity: Set of (16) Valve Spring Style: Beehive-Blue Seat Pressure: 90 lbs. @ 1.80" Open Pressure: 295 lbs. @ 1.25" Outside Diameter: 1.29 Maximum Lift: .57 Solid Height: 1.085 Notes Set of (16)