Exhaust Header for Jeep Wrangler Grand Cherokee (1991-1999) 4.0L

Heavy-Duty Stainless Steel Exhaust Header for 1991-1999 Jeep Wrangler,Grand Cherokee

What it Does: The performance exhaust header replaces the crack-prone factory manifold on 1991-1999 Jeep Wrangler and Grand Cherokee models to eliminate exhaust leaks, lower backpressure, and improve low-end torque delivery.

The Stock Jeep Wrangler,Grand Cherokee Exhaust Manifold Failure

Factory exhaust manifolds on the AMC 242 inline-six engine are plagued by a notorious design flaw: stress cracking at the runner collector junctions. Because the cast iron cylinder head on the YJ, TJ, and ZJ platforms spans a long inline architecture, uneven thermal expansion subjects the OEM thin-gauge manifold to extreme shear forces. Combined with powertrain movement under load, the stock runners fatigue, crack, and leak. This structural failure causes loud exhaust ticks, upstream O2 sensor false-lean readings, compromised fuel trim management, and a noticeable loss of low-rpm crawling power.

The Engineering Solution

Engineered to resolve thermal stress fatigue, this direct replacement header is constructed from high-grade stainless steel with smooth, mandrel-bent primary tubes. The continuous radius bends reduce exhaust flow turbulence, improving cylinder scavenging during the valve overlap cycle. Heavy-duty, precision-machined mounting flanges resist heat warping to provide a flat, persistent seal against the engine block. Reinforced collector joints withstand aggressive engine-mount torque articulation without shearing, safeguarding exhaust gas velocity and restoring crisp throttle response on and off the trail.

Technical Specifications

Compatibility

• 1991-1995 Jeep Wrangler (YJ) 4.0L Inline-6
• 1997-1999 Jeep Wrangler (TJ) 4.0L Inline-6
• 1993-1998 Jeep Grand Cherokee (ZJ) 4.0L Inline-6
• 1999 Jeep Grand Cherokee (WJ) 4.0L Inline-6

Frequently Asked Questions

Does this fit the TJ Wrangler,Grand Cherokee?
Yes, this is a direct fit for the 1991-1999 Jeep Wrangler and Grand Cherokee equipped with the AMC 242 4.0L engine.

Will installation require custom welding or ECM tuning?
No, this assembly bolts directly to the factory downpipe location and operates cleanly within factory ECU closed-loop fuel parameters without tuning.

The Jeep Durability Standard

Built to handle harsh off-camber trail flex and severe high-heat rock crawling, this header assembly withstands brutal operating environments where brittle stock castings consistently split apart.