Boost your engine's performance with the ARP Head Stud Kit - Mitsubishi EVO 4G63 Head (ARP 207-4312F) Custom Age 625, the ultimate choice for head studs. Unlike the popular but difficult-to-work-with L19 material, these CA625+ studs offer the same strength and clamping force without the corrosion risk. With this upgrade, you can confidently run higher boost levels and extend the longevity of your engine. Trust me, this is the best way to take your engine to the next level!