What's in the box:
Stainless Steel Racing Header
Mounting hardware, bolts and gaskets
Product Feature:
Made of High-Quality T304 Stainless Steel Material
TIG Welded CNC Machine Flange
6-2-1 High-Performance Racing Spec. Design
O2 Sensor Insertion and Metal Gasket Included
Increase High Flow Air, Instantly Gain 10 -15 Hp. / Tq.
Specifications:
Brand Name: FLASHARK
Certificate: ISO9001:2000
Application: Automobile Exhaust Header
Material: Stainless Steel
Surface: Mirror Polish
Outlet Size: 3.00",
Primary Tube Size: 1.50"
Number of o2 Locations: 2
Head Flange Thickness: 7/16"
Outlet Flange Thickness: 3/8"
Exhaust Header VS Manifold, which is the better choice?
The structural differences between exhaust headers and manifolds are the material and size. From the material, exhaust headers are made of lighter, thinner steel, while exhaust manifolds are made of thick iron. Exhaust headers are also longer than exhaust manifolds. When in use, exhaust manifolds create back pressure, which lowers performance. Because each cylinder of the engine is given its own tube, however, headers eliminate this problem; thus, allowing the gases to exit without the creation of back pressure. Therefore, exhaust headers are a BETTER choice than an exhaust manifold.
Replacing or upgrading your exhaust header is necessary for both engine performance and sound. Whether on or off the track, exhaust headers provide more horsepower and improved exhaust sound. FLASHARK offers many products to help you create your own custom engine headers. It's really easy and convenient to use: direct bolt-on, no modification needed.
Fitment & Compatibility
- Only compatible with models factory-equipped with 3.8L V6 Supercharged engines
| Brand | Model | Year Range | Full Compatible Specs |
|---|---|---|---|
| Chevrolet | Impala | 2004–2005 | 3.8L L67 Supercharged SOHC V6 Engine |
| Chevrolet | Monte Carlo | 2004–2005 | 3.8L L67 Supercharged SOHC V6 Engine |
Q1: Will these headers fit my 3.8L V6 Naturally Aspirated (L36) engine?
A1: These Flashark racing headers are specifically engineered for the 3.8L L67 Supercharged V6 engine. While they share the same head bolt pattern as the L36 (Naturally Aspirated) engine, please note that the crossover pipe and downpipe routing are optimized for the Supercharged configuration found in the Pontiac Grand Prix GTP and Buick Regal GS. For L36 applications, some custom exhaust work may be required for a perfect fit.
Q2: How much horsepower gain can I expect from the 3800 Series II Supercharged headers?
A2: Installing these high-performance headers typically results in an instant gain of 10-15 Horsepower and Torque. By replacing the restrictive factory cast iron manifolds with 1.5" primary tubes and a 3" outlet, you significantly reduce backpressure, allowing your L67 supercharger to breathe more efficiently and build boost more effectively.
Q3: Are these headers made of real T-304 Stainless Steel?
A3: Yes, our Flashark Exhaust Header Manifolds are constructed from high-quality T-304 Stainless Steel. Unlike cheaper aluminized steel, T-304 offers superior corrosion resistance and durability under the high heat cycles common in supercharged 3.8L V6 engines, ensuring a long-lasting mirror-polished finish and structural integrity.
Q4: Is this a direct bolt-on installation for the Pontiac Grand Prix GTP?
A4: For most 1997-2003 Pontiac Grand Prix GTP models, these headers are designed for a direct bolt-on installation. However, as noted by enthusiasts in the 3800 community, minor adjustments to the crossover pipe or the use of specific clamps may be necessary depending on your specific year and engine mount condition to ensure perfect alignment with the front header.
Q5: Do I need to tune my PCM after installing these L67 headers?
A5: While the car will run without a tune, we highly recommend a PCM recalibration for the L67 Supercharged engine. Headers significantly improve airflow, which can change your air-fuel ratio. A tune will help you maximize the power gains and, more importantly, manage "Knock Retard" (KR) to keep your engine safe under boost.
Q6: Will these headers cause a Check Engine Light (CEL)?
A6: These headers include two O2 sensor bungs to accommodate your factory sensors. However, since the high-flow design changes exhaust velocity and potentially removes or relocates the catalytic converter position, a CEL may occur. This is typically addressed through custom tuning or by using O2 sensor spacers where local regulations allow.
Q7: How do these headers change the exhaust sound of the 3.8L V6?
A7: Upgrading to these stainless steel headers provides a much more aggressive and "throaty" exhaust note compared to the muffled sound of stock cast iron manifolds. You will notice a crisper sound at idle and a prominent racing growl under wide-open throttle, perfectly complementing the supercharger whine.
Q8: Do the headers come with all the necessary gaskets and hardware?
A8: Yes, the kit includes the front and rear headers, the crossover pipe, and the necessary metal gaskets and mounting bolts. For the best long-term seal, some professional installers recommend using OEM-style multi-layer steel (MLS) gaskets, though the included metal gaskets are designed for high-performance racing specs.
Q9: Will I have clearance issues with the steering shaft or spark plug wires?
A9: These headers are CNC machined to maximize clearance in the tight W-Body engine bay. However, because headers radiate more heat than stock manifolds, we strongly recommend using heat sleeves for your spark plug wires or upgrading to angled boots to prevent heat damage, especially on the rear bank.
Q10: Are these headers compatible with the 2004-2005 Chevy Impala SS Supercharged?
A10: Yes! These headers are fully compatible with the 2004-2005 Chevrolet Impala and Monte Carlo equipped with the 3.8L L67 Supercharged engine. They follow the same fitment rules as the Grand Prix GTP, offering a significant performance upgrade for the late-model supercharged W-body platform.
Q11: What is the benefit of the 6-2-1 High-Performance Racing design?
A11: The 6-2-1 design (collecting 3 cylinders into 1 on each side before merging) is optimized for the firing order of the GM 3800 V6. This helps in exhaust scavenging—where the high-velocity pulses from one cylinder help pull the exhaust out of the next—resulting in better volumetric efficiency and more power across the RPM band.
Q12: How much weight do these save over the stock exhaust manifolds?
A12: The stock cast iron manifolds are extremely heavy and prone to cracking over time. Our T-304 stainless steel headers are significantly lighter, reducing the front-end weight of your vehicle, which contributes to better handling and less stress on the upper engine mounts.