ARP Head Stud Kit SUBARU EJ2.0-EJ2.5L HSSU01
Each stud is precisely heat-treated to 190,000 psi. Following heat-treat, each stud is centerless ground to make it as close to perfectly concentric as possible. This procedure results in an exceptionally straight part. Machining the part after heat treating it is difficult and costly because the alloy steel is much harder, but provides a very consistent and reliable part.