ARP DODGE 5.9L DIESEL HEAD STUD KIT. These Head main studs are made from ARP2000 Alloy steel and have a 220,000 psi tensile-strength rating. Following Heat-Treat, Each Stud Is Centerless Ground To Make It As Close To Perfectly Concentric As Possible. This Procedure Involves About Ten Very Slight Cuts And Results In An Exceptionally Straight Part. It’S Important To Note That Lesser Quality Studs Are Not Even Centerless Ground – The Material Is Thread Rolled In Bar Stock Form (Mostly Before Heat-Treat, When The Material Is Easier To Machine). Because Arp Studs Are Manufactured To Such Exacting Tolerances, You Will Note That Gaskets And Cylinder Heads Literally Glide Into Position And Are Perfectly Aligned – Something That Won’T Happen With Inferior Quality Head Studs.