ARP Stainless 3/8-16 12-Point Bolts Pack of 5 — 1.250" Length, 170,000 psi Tensile

ARP 6131250 are polished stainless steel 3/8-16, 12-point bolts sold in packs of five, engineered for high tensile strength and long corrosion resistance.

These bolts combine attractive polished finish with heavy-duty performance for automotive, marine, and trailer applications. Made from ARP's stainless 300 alloy, they resist rust and maintain their appearance while offering tensile strength well above typical Grade 8 fasteners. The compact 12-point head lets you access tight spaces and apply torque with a matching socket. Each card contains five bolts sized to industry standard dimensions for easy replacement or upgrades.

What are the exact dimensions and fitment for these bolts?

Each bolt has a 3/8" major diameter with a 16 threads-per-inch pitch, and the length under the head is 1.250". The wrenching size is sized for a 3/8" drive or matching 12-point socket. These are standard spec bolts meant to replace or upgrade similar 3/8-16 hardware on engines, brackets, and assemblies.

• Diameter: 3/8" (major diameter)
• Thread pitch: 16 TPI (UNC standard)
• Under-head length: 1.250"
• Head style: compact 12-point for tight access
• Wrenching: 3/8" drive compatibility

How strong and durable are ARP's stainless 300 bolts?

These bolts are nominally rated to 170,000 psi tensile strength, giving a notable margin above common Grade 8 hardware. The stainless 300 alloy is formulated to limit corrosion, so the bolts hold up in damp or salty environments better than standard steels. Strength and finish make them suitable where both performance and appearance matter.

• Nominal tensile rating: 170,000 psi
• Proprietary stainless 300 alloy for corrosion resistance
• Polished finish resists discoloration and requires little maintenance
• 12-point head reduces clearance issues during installation

Where would I typically use these 12-point bolts?

They are ideal for engine components, brackets, trim pieces, or any application that benefits from stronger fasteners and a polished look. Because the head is compact, the bolts work well in locations with limited clearance where a conventional hex head won't fit. Their rust-resistant alloy makes them useful on boats, trailers, and coastal vehicles that see moisture or road salt.

• Engine and accessory mounting
• Boat fittings and marine hardware (non-structural)
• Trailer components exposed to the elements
• Visible trim where appearance matters

How are these bolts packaged and how many come in a pack?

ARP supplies these bolts on a convenient card containing five pieces, so you can order the exact quantity needed for small projects or spares. The retail card keeps the fasteners organized and protected until use. Buying the five-pack reduces waste compared with loose bulk and is handy for do-it-yourself repairs.

• Pack count: five bolts per card
• Retail-ready card for organized storage
• Easy to add as replacement or upgrade set

Who is this for? These ARP 6131250 bolts suit mechanics, fabricators, restorers, and boat owners who need stronger-than-standard fasteners with a clean stainless finish. Choose them when you want a compact 12-point head for tight clearances, reliable tensile strength for high-stress joints, and a corrosion-resistant alloy that keeps hardware looking and performing well over time.