SMG/K SET RB26DETT T=1.223009 AN008 NISSAN SKYLINE GT R 1989 2002 RB26DETT Feature For the race the "Independent bead" is the main stream of the water holes or Head Bolt holes. So even if the combustion gas is leaked because of big power setting or degradation, it will reduce the risk of overheat by making it water holes independent bead. By redesigning the water holes area between Head Bolt holes and bore, it will protect head from water flow in because it will prevent the