Product Description

ARP 230-5401 MAIN STUD KIT FOR 2001–2005 GM 6.6L DURAMAX LB7/LLY

Fortify your Duramax bottom end with the ARP 230-5401 Main Stud Kit—precision 8740 chromoly studs engineered to control main cap walk, protect block threads, and hold torque under extreme cylinder pressure. Each kit includes parallel-ground washers, 12-point nuts, and ARP Ultra-Torque™ lubricant for consistent preload. Ideal for stock refreshes, towing builds, and high-boost applications on LB7/LLY engines.

Pair these mains with ARP head hardware for a complete fastener strategy: ARP 230-4201 Head Stud Kit, ARP 230-4202 625+ Head Stud Kit, ARP 230-6301 Rod Bolt Kit, and for later LBZ/LMM engines the ARP 230-5402 Main Stud Kit.

Q: Will ARP 230-5401 fit my truck?
A: Yes—this kit fits 2001–2005 GM 6.6L Duramax LB7 & LLY engines.

Q: Do I need line-hone after installing main studs?
A: It’s recommended to check main bore alignment after torquing; line-hone as required for proper bearing clearance.

Q: What torque lube should I use?
A: Use the included ARP Ultra-Torque™ and follow ARP’s sequence/specs in the instructions for consistent clamp load.

Q: Can I reuse OEM main bolts?
A: Reusing torque-to-yield fasteners is not advised. ARP studs provide repeatable clamping and serviceability.

Fitment

• GM 6.6L Duramax LB7 (2001–2004)
• GM 6.6L Duramax LLY (2004.5–2005)
• Chevrolet Silverado 2500HD/3500HD & GMC Sierra 2500HD/3500HD (applicable model years above)

Specifications for ARP 230-5401