Exhaust Headers For 1987-1990 Jeep Wrangler 4.2L 6 Cyl AMC 258 Engines
Upgrade your Jeep with this high-performance AMC 258 header, designed for 1987–1990 Jeep Wrangler 4.2L 6-cylinder engines. Crafted from polished stainless steel with mandrel-bent 1.50" tubes and a 2.00" collector, it improves exhaust flow, boosts horsepower, and enhances engine sound. Direct bolt-on fit—no modifications needed.
Specifications:
Brand Name: FLASHARK
Certificate: ISO9001:2000
Application: Automobile Exhaust Header
Material: Stainless Steel
Surface: Mirror Polish
Tube Diameter: 1.50"
Collector Diameter: 2.00"
Exhaust Header VS Manifold, which is the better choice?
The structural differences between exhaust headers and manifolds mainly lie in material and design. Exhaust headers are made of lighter, thinner steel, while manifolds are typically built from thick cast iron. Headers are also longer, and because each engine cylinder is connected to its own individual tube, they help reduce back pressure—unlike manifolds, which often restrict exhaust flow and decrease performance.
By minimizing back pressure, exhaust headers improve engine efficiency, allowing exhaust gases to exit more freely. This results in better performance, increased horsepower, and enhanced sound—making headers the better choice over traditional manifolds, especially for engines like the AMC 258 4.2L 6-cylinder found in the 1987–1990 Jeep Wrangler.
Upgrading or replacing your exhaust header is essential for those looking to boost both engine output and exhaust tone. Whether you're on the street or off the trail, FLASHARK offers a range of performance headers to meet your needs. Our designs are direct bolt-on, requiring no modifications, making installation quick and convenient.
Fitment & Compatibility
| Brand | Model | Year Range | Full Compatible Specs |
|---|---|---|---|
| Jeep | Wrangler | 1987-1990 | 4.2L 6 Cyl AMC 258 Engine (2WD Only) |
Q1: Will this header specifically fit my 1987-1990 Jeep Wrangler 4.2L?
A1: Yes, this Flashark exhaust header is custom-engineered to perfectly fit the 1987, 1988, 1989, and 1990 Jeep Wrangler YJ models equipped with the 4.2L 6-cylinder (AMC 258) engine.
Q2: Can this amc 258 header improve my Jeep's horsepower?
A2: Absolutely. By replacing the highly restrictive factory cast-iron manifold with our mandrel-bent tubular header, you heavily reduce exhaust back pressure. This allows the AMC 258 engine to breathe more freely, resulting in noticeable increases in both horsepower and low-end torque—ideal for trail crawling and highway driving.
Q3: What material is used to construct this jeep yj 4.2 header?
A3: This performance header is constructed from high-quality, durable stainless steel and features a sleek mirror polish finish. Stainless steel offers vastly superior resistance to rust, heat fatigue, and cracking compared to standard OEM cast-iron manifolds.
Q4: Does this fix the common ticking noise on the amc 258 exhaust manifold?
A4: Yes! The factory AMC 258 exhaust manifolds are notorious for cracking over time, which causes an annoying ticking exhaust leak. Upgrading to this premium stainless steel header permanently resolves that issue while providing an instant performance boost.
Q5: Is this jeep 258 header a direct bolt-on installation?
A5: Yes, it is designed as a direct bolt-on replacement for your original 4.2L manifold, meaning no major custom welding is required. However, as with many vintage Jeep YJ upgrades, some minor adjustments—such as slightly elongating a bolt hole, filing a flange edge near the #5 cylinder, or clearancing the driver's side engine mount—may be necessary for a perfect fit.
Q6: Are the gaskets and mounting hardware included with these wrangler headers?
A6: Yes, this complete header kit includes the super-thick exhaust flanges, high-quality exhaust gaskets, and the necessary hardware required to bolt it up to your engine block.
Q7: How will this header change the sound of my Jeep YJ exhaust?
A7: Upgrading to this stainless steel tubular header completely transforms your exhaust note. It eliminates the choked, raspy sound of a cracked manifold and delivers a much deeper, smoother, and aggressive tone that perfectly complements the classic Wrangler character without being obnoxiously loud.
Q8: What are the tube and collector sizes on these amc 258 headers?
A8: To maximize exhaust gas scavenging on the 4.2L inline-6, these headers feature mandrel-bent 1.50-inch primary tubes that merge efficiently into a high-flow 2.00-inch collector.
Q9: Will this fit older Jeep CJ7 models with the 4.2L AMC 258?
A9: While the AMC 258 engine block is physically the same in the CJ7, this specific header is primarily routed and verified for the 1987-1990 Jeep Wrangler YJ chassis. Fitting it to a CJ7 may require custom exhaust routing from the collector backward to avoid frame or steering shaft interference.
Q10: Why should I upgrade from an iron manifold to a tubular header?
A10: Cast-iron manifolds are heavy, retain a massive amount of heat, and merge exhaust gases inefficiently, choking your engine. Tubular headers dedicate an individual, smooth-flowing pipe to each cylinder. This eliminates turbulence and back pressure, dramatically improving throttle response, fuel efficiency, and overall power on your 4.2L.
Q11: Will installing this header require me to buy a new cat-back exhaust?
A11: Not necessarily. The 2.00-inch collector is designed to mate up with standard exhaust setups. However, some customers might need a slight exhaust pipe extension or adjustment at the collector doughnut connection to perfectly marry this header to an older or modified existing exhaust system.
Q12: Is there an extra fee exhaust header for 1987-1990 jeep wrangler 4.2l 6 cyl delivery?
A12: No, the price you see for this premium header is exactly what you pay for the product. Please check our shipping policy page for exact shipping rates, but Flashark prides itself on transparent pricing with no hidden product fees.