Developed by one of the top NASCAR Winston Cup Engine Builders, this innovative new tool precisely grooves the lifter bore to ensure that pressure fed oil is directly injected into the contact area between the lifter and camshaft. This increased oiling significantly reduces wear on the camshaft and lifters and decreases the risk of premature failure during break in. This machining operation to the block is quick, easy, inexpensive and is the best insurance for a new camshaft. The replaceable carbide cutters are also available separately. Comes complete with gooving tool, cutter and handle. Note: The engine must be disassembled to use this tool. Cut groove to .009 to .012.