Description ARP Head Stud Kit for 2001-2016 GM 6.6L Duramax ARP 230-4201 Fits all LB7, LLY, LBZ, LMM & LML Engines ARP fasteners makes the best and stronger engine head studs on the market today. Your 6.6L came from the factory with head bolts. The factory head bolts were designed to stretch but over time the bolts stretch past the designed length and allow the gaskets to leak. With ARP head studs there is no more stretch and therefor no longer issues with blown head gaskets. All ARP studs are heat treated and feature rolled threads 8740 alloy is rated better than aircraft quality.
