Tomei Head Stud Kit - Subaru EJ20 / EJ25SKU: 193112
Tomei head stud kits offer much higher stength over factory bolts allowing more boost and higher power levels.
In order to secure the performance required of head gaskets, such as cooling, rigidity, and sealing, it is necessary to strengthen the joining of the cylinder head and cylinder block. However, in combination with a common bolt and nut, no matter what strength bolt is used, bolting power concentrates on from third mountains to the 1st mountain of the screw, and the total bolting power cannot be increased beyond a certain value. Moreover, excessive stress is concentrated and may damage the bolt. Stud bolt, on the other hand, is applied dynamic design to its threading so that the bolting force is dispersed to all the threads and higher bolting power is generated.