All of the components of the Lunati Hydraulic Race Lifters are held to higher tolerances for superior performance. The plunger has a much tighter fit to the body, which reduces the amount of leaked pressure, keeping the lifter stiffer and more responsive. The one-piece pushrod seat is heat treated, which prevents the seat from damage and is equipped with a heavy duty snap ring to reduce wear and increase durability. The Hydraulic Race Lifters have a pre-load that can be set to .000"-.030" and are the best option for racers looking to go beyond a stock replacement lifter.