Factory head bolts can stretch under higher boost, heavy towing, or elevated cylinder pressure—raising the risk of a lifted head and blown gasket.

The ARP 247-4207 head stud kit is for 3.9 Cummins 4BT. It replaces stretch-prone hardware with ARP fasteners built for high-load diesel use.

What you get

• Custom Age 625 Plus material (typical tensile ~260,000 psi per ARP)
• ARP cylinder-head studs with nuts and washers as supplied in the kit
• ARP Ultra-Torque assembly lubricant (when included per ARP instructions)
• Fitment: 3.9 Cummins 4BT
• Follow ARP installation instructions for your exact kit

Specs

• ARP part number: 247-4207
• Material: Custom Age 625 Plus
• Typical tensile strength: ~260,000 psi (ARP material data)
• Thread reference from ARP instructions: M12 x 1.75, M8 x 1.25

Built for diesel owners who tow, tune, or rebuild—and want head-clamping they can trust. Install with the ARP instruction sheet for 247-4207—use the supplied lubricant and torque or stretch procedure. Verify fitment for your exact engine and year before ordering.