ARP Pro Series head studs are a common choice in all-out competition engine builds thanks to consistent materials and tightly controlled manufacturing.

• Made from premium grade 8740 alloy
• Heat-treated to 200,000 psi with studs held vertically in dedicated racks to promote complete heat penetration
• Centerless ground after heat-treat for near-perfect concentricity
• Multiple light centerless-grind passes (about ten) for an exceptionally straight stud
• Threads are rolled in bar stock form, typically before heat-treat when the material is easier to machine

Because these studs are produced to exact tolerances, gaskets and cylinder heads can glide into position and align cleanly during assembly—an advantage you won’t typically see with lower-quality studs that aren’t centerless ground.