New Jeep 4.0L OHV Cylinder Head – Fits Casting Numbers # 0331, 0630, 7120 W/ Head Gasket and Bolts, Full Pushrod & Rocker Arm Set

New Jeep 4.0L OHV Cylinder Head – Fits Casting # 0331, 0630, 7120 w/ Gasket Set, Bolts, Pushrods & Rockers

Restore your Jeep’s legendary performance with a reinforced, crack-resistant cylinder head kit—complete with a head gasket set, bolts, 12 pushrods, and a full rocker arm assembly.

The Jeep 4.0L inline-six is an icon of durability, but its factory cylinder heads (specifically the 0331 casting) are notorious for cracking between the #3 and #4 cylinders. Our premium aftermarket replacement solves this with a thickened deck and reinforced water jackets. This “Universal” design is a direct bolt-on upgrade for all 4.0L engines from 1991 to 2007, providing a permanent solution for your Cherokee, Wrangler, or Grand Cherokee.

🛠️ 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, ensuring your oiling system remains uncontaminated.
• 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: We pressure-test every head to 60 PSI to verify that the casting is 100% free of porosity leaks or internal defects.
• Dimensional Inspection: Our technicians perform a multi-point inspection of the gasket-sealing surface to ensure it is perfectly flat and meets tight OEM tolerances.
• Professional Assembly: Valvetrain components are installed in a clean-room environment, with spring heights and seal seating verified for immediate installation.
• Vacuum-Seal Verification: Every intake and exhaust port is Vacuum Tested to guarantee a 100% airtight seal between the valves and seats for maximum compression.

📊 Technical Specifications

• Engine: Jeep 4.0L Inline 6 (OHV)
• Year Range: 1991-2007
• Replaces Casting Nos: 0331, 7120, 0630
• Material: High-Strength Reinforced Cast Iron
• Each Cylinder Head Includes: Valves and Springs Installed
• Additional Hardware: Head Gasket Set, Head Bolt Set, 12 Pushrods, and Full Rocker Arm Set

🚛 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