Mechanical Lifters (Also Called "Solids") Should Never Be Used On a Hydraulic Cam. This Will Result In a Rapid Cam, Lifter and Valve Train Wear and Failure. For The Same Reasons, Hydraulic Lifters Should Never Be Used On a Mechanical Cam. When Increased Power and Rpm Is Required a Roller Cam (Hydraulic Roller Or Mechanical Roller) Is Always The Best Choice. However, If Buget Or Track Rules Require a Flat-Tappet Mechanical Cam Crane Offers Many Different Choices Of Mechanical Cams and Lifters Well Suited To Your Application. Mechanical Lifters Are Actually "Solid" (Except Those Used For Oil Control) Internally. They Are Also Noiser Than Hydraulic Lifters and Require Periodic Valve Lash Adjustment. Crane Lifters, Hydraulic and Mechanical, Are Made From The Finest Quality Alloy Steels, Metallurgically Designed To Be Compatible With Cam Lobes and Precision Machined On CNC Equipment.Pit Stop USA offers Crane Cams Mechanical Lifters (16) - Ford 62-95 V-8 221-302 & 351W 99257-16 at low everyday prices. Be sure to check out all of our products from Crane Cams including Crane Cams Hydraulic Lifters - Small Block Ford.