Brian Crower Jeep 4.0L/4.2L Inline 6 (AMC) Hydraulic LiftersBrian Crower Jeep 4. 0L 4. 2L Inline 6 (AMC) Hydraulic Lifters These BrianCrower hydraulic lifters from feature a patented, constant orifice metering valve that precisely meters oil to the rocker arms. Continuous contact between the metering valve and the precisely coined bottom surface of the pushrod seat is maintained throughout the engine's rpm range, eliminating excessive oiling at high speeds. The pushrod seat is made of a special powdered metal