The ARP 218-4701 is a professional-grade cylinder head stud kit
engineered for high-performance and competition engines. Built from
premium 8740 chrome moly steel and heat-treated to 200,000 psi,
these studs deliver exceptional strength and reliability for
demanding applications.
Key Features:
- Premium 8740 chrome moly alloy rated at 200,000 psi tensile
strength
- 12-point head design for improved wrench engagement
- Vertical rack heat-treatment ensures complete and uniform heat
penetration
- Centerless ground for precise concentricity and perfect
alignment
- Thread rolled after heat-treat for 10x better fatigue
strength
- Undercut short studs equalize stretch for consistent clamping
force
- Includes hardened parallel-ground washers for even load
distribution
Manufacturing Excellence:
ARP's manufacturing process sets the standard for fastener
quality. Each stud is precisely heat-treated in vertical racks
rather than batch-processed, ensuring consistent properties
throughout. The centerless grinding process involves multiple
precision cuts to achieve exceptional straightness and
concentricity, allowing cylinder heads and gaskets to align
perfectly during installation. Thread rolling is performed after
heat-treatment, which significantly increases fatigue resistance
compared to pre-heat-treat threading methods used by
competitors.
Performance Advantages:
Head studs offer significant advantages over traditional head
bolts. During installation, studs stretch only along the vertical
axis when the nut is torqued, providing more accurate and
consistent clamping force. Bolts, by contrast, experience both
torsional and tensile stress simultaneously, leading to less
predictable loading. The undercut design on shorter studs helps
equalize stretch across all fasteners, compensating for head gasket
compression and reducing the risk of gasket failure. This results
in superior engine sealing and consistent performance.
Installation Notes:
Studs should be installed finger-tight in a relaxed state?never
force them in using a jammed nut. Apply torque only to the nut
during final assembly. After initial engine operation, re-torque
all fasteners to compensate for head gasket compression. The
12-point head design and wide-area flange eliminate the need for
valve train removal when retorquing cylinder heads.
Trusted by professional engine builders across all forms of
motorsport, ARP Pro Series studs represent the highest quality
fastener solution available for competition and high-performance
engines.