MOREL LIFTER SET - LS - HIGH RPM - HYDRAULIC - 5294 The Hi-RPM hydraulic lifters are made from a billet body and have a clipped axle. These lifters have 7000+ RPM capability with .120 plunger travel and have an 80% fill rate with the test oil. These lifters have a .750 diameter roller wheel for the .842 & .875 diameter lifters and a .810 diameter roller wheel for the .903 diameter lifters. The Internal tolerances are much tighter in this series. Do not use oil heavier than 5W40! Recommended spring pressures are 100-225 lbs seat pressure and 350-550 lbs open pressure.