ARP Cylinder Head Studs for BMC B Series 12-pt Nuts

Professional-Grade Cylinder Head Retention for BMC B-Series and Triumph B-Series Engines

The ARP 206-4202 Head Stud Kit delivers race-proven clamping force for BMC B-Series and Triumph B-Series engines. Built from 8740 chrome moly steel and finished in black oxide, the ARP 206-4202 replaces factory head bolts with precision-machined studs that provide more accurate torque readings, superior clamp load, and far greater resistance to loosening under sustained heat and pressure. Whether you are rebuilding a classic British roadster, building a performance street engine, or preparing for competition, the 206-4202 is the correct fastener for the job.

Key Features

• ARP 206-4202 machined from 8740 chrome moly steel for superior tensile strength
• Black oxide finish resists corrosion and protects stud threads during installation
• 12-point nuts allow access in tight head areas and provide precise torque application
• 3/8-inch UNC block threads and 3/8-inch UNF nut threads for secure engagement
• Precision-machined threads eliminate cross-threading and ensure repeatable clamp load
• Seven-stud kit covers the full BMC B-Series and Triumph B-Series head bolt pattern
• ARP 206-4202 provides more accurate torque readings than head bolts due to reduced friction
• Manufactured and quality-controlled in the USA by ARP Fasteners

Fitment

Specifications

What's Included

• 7x ARP 206-4202 8740 chrome moly head studs
• 12-point nuts
• Hardened washers
• ARP assembly lubricant

About ARP

ARP (Automotive Racing Products) has been the global leader in high-performance fasteners since 1968. Every ARP stud and bolt is manufactured in Ventura, California using proprietary alloys and precision machining processes that exceed OEM specifications. The 206-4202 is part of ARPs Professional Series line, engineered to meet the demands of performance street, track day, and full competition applications. ARP products are used by professional race teams worldwide and are trusted by builders who cannot afford fastener failure.

Related Parts on Our Site

• Shop All ARP Fasteners at blackopsautoworks.com
• Engine Components Collection
• Head Stud and Bolt Kits Collection

Frequently Asked Questions

The ARP 206-4202 is a professional-grade cylinder head stud kit designed specifically for BMC B-Series and Triumph B-Series engines. It includes seven 8740 chrome moly studs with 12-point nuts and hardened washers that replace factory head bolts for improved clamping force and torque accuracy.

The 206-4202 is engineered for the BMC B-Series engine family and the Triumph B-Series engine, covering classic British vehicles built from the 1950s through the early 1980s including MGB, Morris Minor, Austin, and Triumph applications.

Head studs thread into the block while stationary, allowing the nut to be torqued without rotational force on the stud itself. This eliminates friction variables that affect torque readings with head bolts, resulting in more even and accurate clamping load across the entire gasket surface.

The 206-4202 studs are manufactured from 8740 chrome moly steel, the same alloy ARP uses across its Professional Series line. This material provides tensile strength far exceeding OEM head bolts while maintaining enough ductility to resist fatigue cracking.

The block end of the 206-4202 uses 3/8-inch UNC coarse threads for engagement into the engine block. The nut end uses 3/8-inch UNF fine threads, providing finer adjustment and more precise torque control at the clamping surface.

No specialty tools are required beyond a standard torque wrench. A 12-point socket sized for the included nuts is needed. ARP recommends using the included assembly lubricant on all threads and under the washer face for accurate torque readings.

Always refer to the ARP instruction sheet included in the kit for the specific torque value. Torque specifications vary based on lubricant used and should never be estimated. Using ARP moly lube, the recommended value is printed on the included spec sheet.

ARP studs can typically be reused if they show no signs of stretching, thread damage, or corrosion. Inspect each stud visually and verify threads are clean before reinstalling. Replace any stud that does not thread smoothly by hand.

Yes. This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. See the Prop 65 warning at the bottom of this page.

All ARP fasteners including the 206-4202 are manufactured in Ventura, California, USA. ARP controls the entire production process in-house from raw material selection through final quality inspection.

Installation Instructions

1. Clean all head bolt holes in the block thoroughly with a tap and blow out debris with compressed air.
2. Apply ARP assembly lubricant to the UNC block threads of each 206-4202 stud.
3. Thread each stud into the block by hand until finger-tight. Do not use an impact tool.
4. Install a new head gasket following the gasket manufacturer's orientation requirements.
5. Lower the cylinder head carefully over the studs.
6. Apply ARP assembly lubricant to the UNF threads and under the washer seating face.
7. Thread on hardened washers and 12-point nuts by hand.
8. Torque the nuts in the sequence specified by the engine manufacturer in three equal stages.
9. Final torque value: refer to the ARP specification sheet included in the kit.
10. After initial heat cycles, re-check torque and retorque if needed following ARP guidelines.

WARNING: This product can expose you to chemicals including nickel compounds, which are known to the State of California to cause cancer, and carbon monoxide, which is known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.