Lifter,8 Required for 4 Cylinder,12 Required for 6 Cylinder, And 16 Required for V8,72-79 3.8L,72-90 4.2L,72-81 5.0L,83-02 2.5L,1987-96 4.0L. ver time all internal engine wear surfaces become worn. This is true for crankshaft journals, connecting rods, camshaft lobes, piston rings, bearings, etc. When rebuilding a worn out engine you'll need to replace them all in order to regain the engine's original performance. And, let's face it, Jeep's need all the power we can get.