Although hydraulic lifter that is used in stock engines of RB20, VG30 or CA18 are contributed in making it maintenance free, it be comes the hindrance of high-speed rotation interns of tuning the engine. Also, since hydraulic lifter cannot adjust its height, it is impossible to use high lift camshaft. Accordingly, the tuning range and performance of RB20, VG30 and CA18 were restricted by H-lifter. On the other hand, In addition, it is required to use special camshaft designed only for the solid type camshaft, which has enlarged buffer part of the valve clearance.