COMP Cams Lifters 882-12 Hi-Tech Hydraulic Lifters have a greater bleed rate, which greatly increases vacuum, throttle response and noise. Hi-Tech Lifters were designed primarily for extremely hot street machines or racing applications where a vacuum rule is in place or where you must run a Hydraulic cam. Hi-Tech Lifter, A/CRS COMP Cams Hi-Tech Hydraulic Lifter for Small and Big Block Chrysler and AMC V8, Set of 12 COMP Cams Hi-Tech Lifter A/CRS