ARP Main and Block Bolts Subaru WRX 2004-2014 / STI 2004-2018
ARP Subaru EJ20, EJ25, & EJ257 Main Bolts are crafted from 8740 forged chrome moly and feature generous under-head radius and rolled threads for excellent reliability. The threads are rolled after heat-treating, giving them 1000% longer fatigue life than ordinary bolts. Paralell-gound hardened washers are included. These are crankcase through bolts for all EJ series motors.