ARP head studs provide superior cylinder head clamping and reduced distortion and should be considered essential for every performance engine build. The manufacturing process involves centerless grinding of the blanks for near perfect concentricity and thread rolling after the heat treatment for significantly increased fatigue strength. Standard material is ARP2000 alloy with a 220ksi tensile strength. Custom Age 625+ is an optional high strength (260ksi) material for more demanding applications.
NOTE: EJ DOHC head stud kits can be used in FA20DIT applications even though there is a specific FA20 kit.
Usually ships in 2 to 3 days.
What is the advantage of head studs over head bolts? A properly installed head stud will provide more accurate and consistent clamping force which will improve head gasket reliability. A head bolt will twist as it is being torqued meaning that only a portion of the torque loading will be in the vertical direction.
When is it necessary to use a Custom Age 625+ head stud kit over the standard ARP 2000? The higher tensile and yield strengths of Custom Age 625+ allows the use of increased torque values to improve the head clamping force. Extreme applications which are prone to head gasket issues will benefit from the high strength studs. The higher forces at the block will result in increased cylinder distortion which will need to be corrected. We generally suggest an upper limit of 450bhp for the ARP2000 material and 600bhp for the 625+ material.
