ARP Case Bolt Kit Main Subaru Impreza WRX 02-14 / STi 04-20 EJ205 EJ255 EJ257

When rebuilding an engine, there are several stock parts you wont want to reuse. Stock case bolts stretch over time, and even more so each time they are re-tightened. Each time they stretch, their clamping abiltiy decreases. If case bolts stretch, bearings can spin, and possibly even worse. Case bolts are a low cost item that can mean the difference between your engine lasting, or not. Use ARP Case Bolts for your engine build.
Far superior to any other main bolt kit offered for use in competition engines. ARP main bolts are designed to meet the exacting standards and demands of professional engine builders. Forged from 8740 chrome moly, all bolts feature generous under-head radius and rolledthreads for the utmost reliability. The threads are rolled after heat-treating, which gives themabout 1000% longer fatigue life than most main bolts, which are threaded prior to heattreating.Available in the popular High Performance Series, which, at a nominal rating of 180,000 psi, is a premium replacement for OEM fasteners, or the 200,000 psi nominal rated Pro Series, application-specific main boltswith reduced wrenching head and are designed for use in competition applications. Parallel-ground,hardened washers are included with each kit.