Upgrade clamping force and gasket reliability with this ARP2000 head stud kit. ARP’s quench-hardened, tempered alloy delivers significantly higher tensile strength than OE bolts and provides more consistent, repeatable preload.

• Material: ARP2000 alloy steel, heat-treated
• Preload consistency: Studs provide more uniform, accurate torque vs. OE torque-to-yield bolts
• Performance headroom: Supports high boost, towing, and performance builds when installed and torqued correctly

Supplier data indicates ~15% higher clamping load at ~75% of yield, and up to ~30% at ~85% of yield (vs comparable fasteners).

• 18 × ARP2000 cylinder head studs
• 18 × hardened parallel-ground washers
• 18 × 12-point nuts
• ARP Ultra-Torque fastener lubricant (sachet)

• Isuzu 4JJ1 (D-MAX / MU-X / Colorado RC / RA7 Rodeo and related 4JJ1 platforms)
• Isuzu 4JX1TC applications

If you’re unsure, send your VIN/engine code and we’ll confirm before dispatch.

• Higher clamping load for boosted and heavy-duty use
• Better load distribution and torque accuracy for head gasket sealing
• Serviceability: studs can be re-used if they remain in spec (inspect and measure)

Ultimately: improved sealing reliability and reduced risk of head gasket issues in performance applications.

• Chase threads to the bottom: Use a suitable bottoming tap. Clean/blow out debris and verify threads are fully cut and dry before assembly.
• Under-cam stud length: The studs that sit under the camshafts are too long in current design. Shorten the top (hex-end) of 8 studs so they do not interfere with correctly tightening the rocker arm shafts.
• Washer recess depth: Either omit washers on those under-cam locations (not preferred) or machine the cylinder head’s washer recesses an additional ~3.5 mm (preferred). Even if you machine the recesses, those studs still need to be shortened.
• Lube: Use ARP Ultra-Torque on the nut/washers and stud threads per ARP instructions. Do not oil the block threads unless ARP specifies.

Professional installation recommended. Always measure, trial-fit, and follow ARP’s official torque procedure for your thread size and lube.

• Install studs hand-tight into the block (finger tight only unless ARP specifies otherwise).
• Fit head, washers, and nuts with ARP Ultra-Torque applied to nut threads and under the nut face/washer.
• Torque in multiple equal steps following the factory head-tightening pattern (e.g., 3–4 steps to final value as per ARP’s chart for your fastener size/lube).
• Allow a short dwell, then re-check final torque in sequence.

Follow the ARP instruction sheet included with the kit for exact torque values with Ultra-Torque.

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