ARP HEAD STUD KIT Custom Age 625 3SGTE Celica GT4. The ARP Custom Age 625 material offered by ARP is the one of the most expensive and strongest material offered in a stud. These will provide over 1000psi MORE clamping force over standard 1/2" studs and they are a direct swap! WHAT IS CUSTOM AGE 625 ?

You may have heard of the popular L19 upgrade for Head studs, Main Studs, Rod Bolts, etc. The L19 material is stronger than the ARP 8740 or even ARP 2000 materials, however L19 is difficult to work with.

You cannot touch L19 with your bare hands or the oils from your fingers will corrode the studs. CA625 material is just as strong, offering an increase in clamping force, without the difficult-to-deal-with issues that L19 has. These CA625 studs will allow you to run even more boost without the head lifting, and will ensure the longevity of your engine even more. If you are looking for the best way to do it, this is the way to go.