This custom-made ARP Head Stud Kits suiting the 4-cylinder engines are simply the best stud setup available in the market today. They are manufactured using premium quality heat-treated 8740 chrome moly steel. This ARP Head Stud Kit is meant to replace the original Ford head bolt
ARP uses a premium quality (SDF and CHQ grade) 8740 chrome moly steel alloy that is rated superior to aircraft quality. Each stud is placed vertically in special racks and heat-treated to ensure 360° penetration. This procedure is far superior to other methods of dumping items in a large bin and batch treating.
Following heat-treatment, each stud is shot-peened to remove surface irregularities, and then undergoes a centreless grinding process to ensure they are perfectly concentric. This procedure involves about ten machining steps for an exceptionally straight part.
The studs are then thread rolled after heat-treatment, which gives them about 1000% (10 times) more fatigue strength than those studs that are threaded prior to heat-treatment.
ARP Nuts are manufactured in a multi-step process that "blanks” the hex and 12-point nuts and is followed by a CNC-threading process which taps each nut with an accuracy of .001K (5 times higher than the aerospace standard). This ensures an exceptionally close-tolerance fit between the bolt/stud and nut.