Direct Lube Extreme Duty Chevrolet 265-454 Mechanical Flat Tappet Lifters Today’s cams have more aggressive lobes. Increasing oil supply to these lobes is critical. A precision “E.D.M.” laser burns a .021” hole in the center of the face of the lifter. This allows a constant oil supply to the cam lobe, allowing higher valve spring pressures, more aggressive profiles and reduced lobe wear. Made in the USA!