ARP 203-4706 Custom Age Head Stud Kit - B58 625+

The ARP 203-4706 Custom Age 625+ Head Stud Kit is engineered for high-performance B58 engine builds found in the Toyota GR Supra A90/A91 and various BMW chassis. This premium head stud kit is designed to maintain critical head-to-block clamping force under extreme boost and power conditions where factory head bolts would stretch and fail.

Custom Age 625+ Material Advantage:

This kit features ARP's proprietary Custom Age 625+ material with a tensile strength of 260,000 psi, substantially higher than the 190,000 psi rating of standard ARP2000 studs. CA625+ delivers the superior strength of L19 material without the handling difficulties—L19 requires gloves during installation due to corrosion from skin oils, while CA625+ offers equivalent strength with easier installation.

Key Features:

• Custom Age 625+ material rated at 260,000 psi tensile strength
• 12-point nuts for precise torque application
• Hardened parallel-ground washers for even load distribution
• Centerless ground studs for exceptional concentricity
• Thread-rolled after heat treatment for 10x better fatigue strength
• Cold-forged construction ensures molecular integrity
• Precisely heat-treated in vertical racks for complete penetration

Application:

Designed specifically for the turbocharged inline 6-cylinder B58 engine (B58B30M1, B58B30O1) found in 2020+ Toyota GR Supra and compatible BMW models. Ideal for high-boost forced induction builds where maximum clamping force is critical to prevent head gasket failure.

Each ARP Pro Series head stud kit includes all necessary studs, 12-point nuts, hardened washers, and ARP Ultra-Torque assembly lubricant to ensure proper installation and accurate torque readings.