It is one of the most sufficient ways of making high performance engine to install the high lift camshaft. However, in some engines, it cannot be done to raise the lift without applying smaller base circle of camshaft. Usually, it is dealt with making special valves or grinding valve sheets or installing thick valve shims, yet, all the above taking risks of falling reliability of the engine and raising cost of processing. Tomei's valve lifter higher than stock so as to high lift camshaft can be installed only by replacing the valve lifter.