ARP Cylinder Head Stud Kit - Subaru WRX VA / Levorg / Forester / BRZ / Toyota 86 (FA20)

ARP Cylinder Head Stud Kit - FA20 | Subaru WRX VA / Levorg / Forester / BRZ / Toyota 86

Part Number: 260-4301

The choice of virtually every top professional engine builder, ARP Pro Series head studs set the benchmark for head clamping hardware. When you're building an FA20 for serious power, there is no better stud on the market.

Premium 8740 Chrome Moly Steel

ARP uses a premium grade 8740 alloy rated far superior to standard "aircraft" quality material. Each stud is vertically rack-mounted and precisely heat-treated to 200,000 psi — ensuring complete, even heat penetration throughout the part. This is in stark contrast to lesser manufacturers who batch-treat parts in baskets with inconsistent results.

Centerless Ground for Perfect Concentricity

Following heat-treat, every stud is centerless ground through approximately ten precision passes, producing an exceptionally straight, concentric part. Many competing studs skip this step entirely — thread rolling bar stock before heat-treat when the material is easier to machine, at the cost of final part quality. The result with ARP is that gaskets and cylinder heads glide into position and align perfectly every time.

Thread Rolled After Heat-Treat

ARP studs are thread rolled after heat-treat, delivering approximately 1,000% better fatigue strength compared to studs threaded prior to heat-treat — a shortcut that remains common practice across the industry. It's harder on tooling and costs more to produce, but the fatigue resistance advantage is significant in high-boost applications.

Undercut Design for Consistent Clamping Force

Select ARP studs feature a specially undercut shank that equalises the stretch between studs of different lengths. This produces a more consistent clamping force across the head, compensating for head gasket compression during installation — helping prevent blown gaskets and ensuring optimum engine sealing under sustained boost.

Vehicle Fitment