Description
New Jeep 4.0L Inline 6 Cylinder Head – Reinforced Universal Casting (1991-2007)
Upgrade your Jeep’s legendary 4.0L engine with a reinforced, crack-resistant cylinder head designed to outperform the 0331, 7120, and 0630 factory castings.
The Jeep 4.0L inline-six is famous for its longevity, but factory heads are notorious for cracking between the #3 and #4 cylinders. Our premium aftermarket replacement features a thickened deck and reinforced water jackets to eliminate these common failure points. This universal casting is a direct “bolt-on” upgrade for all 4.0L Jeep engines from 1991 to 2007, whether your original head used a distributor or coil-pack ignition.
🛠️ In-House Machining Process
- Debris-Free Preparation: Every new casting is chemically cleaned and blown out to remove all residual machining oils and manufacturing debris. This ensures your oiling system remains uncontaminated from the first start-up.
- In-House Precision Machining: We perform all final machine work in-house, including precision valve seat cutting and guide sizing, to ensure perfect geometry and clearances.
- Pressure & Integrity Testing: To go beyond the factory standard, we pressure-test every head to 60 PSI. This verifies that the casting is free of porosity leaks or internal defects.
- Dimensional Inspection: Our technicians perform a multi-point inspection of the gasket-sealing surface. This ensures the head is perfectly flat and meets tight OEM tolerances for a flawless fit.
- Vacuum-Seal Verification: Every intake and exhaust port is Vacuum Tested. This guarantees a 100% airtight seal between the valves and seats, ensuring maximum compression and peak performance right out of the box.
📊 Technical Specifications
- Engine: Jeep 4.0L Inline 6 (OHV)
- Year Range: 1991-2007
- Replaces Casting Nos: 0331, 7120, 0630
- Material: Heavy-Duty Cast Iron (Reinforced)
- Each Cylinder Head Includes: Valves and Springs Installed
🚛 Fitment Data
Common Applications:
- Jeep Wrangler (YJ/TJ/LJ): 1991-2006
- Jeep Cherokee (XJ): 1991-2001
- Jeep Grand Cherokee (ZJ/WJ): 1993-2004
- Jeep Comanche (MJ): 1991-1992
[+] Click to View Full Detailed Fitment List
CHEROKEE 91-95 6-242 (4.0L)
COMANCHE 91-92 6-242 (4.0L)
GRAND CHEROKEE 93-95 6-242 (4.0L)
WRANGLER 91-95 6-242 (4.0L)
CHEROKEE 96-99 6-242 (4.0L)
GRAND CHEROKEE 96-98 6-242 (4.0L)
WRANGLER 97-99 6-242 (4.0L)
CHEROKEE 00 6-242 (4.0L)
CHEROKEE 01 (4.0L)
GRAND CHEROKEE 99-04 4.0L (6 cylinder)
WRANGLER 00-02 6-242 (4.0L)
WRANGLER 03-06 4.0L
COMANCHE 91-92 6-242 (4.0L)
GRAND CHEROKEE 93-95 6-242 (4.0L)
WRANGLER 91-95 6-242 (4.0L)
CHEROKEE 96-99 6-242 (4.0L)
GRAND CHEROKEE 96-98 6-242 (4.0L)
WRANGLER 97-99 6-242 (4.0L)
CHEROKEE 00 6-242 (4.0L)
CHEROKEE 01 (4.0L)
GRAND CHEROKEE 99-04 4.0L (6 cylinder)
WRANGLER 00-02 6-242 (4.0L)
WRANGLER 03-06 4.0L
📦 Core Return & Warranty
- ❌ NO CORE REQUIRED — No core fee, no return needed. Your old part is yours to keep or dispose of as you see fit.
- Warranty: 2-Year Unlimited Mileage Warranty included. Click here for Warranty details.
- Please Note: Parts, marine, and performance items carry specific warranty limitations — please review our full Warranty Policy for details.
