Stainless Works GT350HCAT 1-7/8" Long Tube Headers Catted 2015-2020 GT350/GT35

Vehicle Fitment

• 2015-2020 Ford Mustang Shelby GT350 (5.2L V8 Voodoo)
• 2015-2020 Ford Mustang Shelby GT350R (5.2L V8 Voodoo)

Fitment Notes

• Fits the 5.2L Voodoo flat-plane crank V8 engine only. Does not fit the standard 5.0L Coyote GT or any other Mustang variant.
• Factory Connect design - connects directly to the factory exhaust slip-fit connection point, allowing use with the unmodified stock cat-back exhaust with no additional parts, mid-pipe, or fabrication required. Also compatible with Stainless Works Factory Connect cat-back exhaust systems.
• Convertible fitment is not confirmed. Fitment is verified for Fastback (coupe) body styles on both the GT350 and GT350R.
• Engine tuning is required after installation for proper air/fuel ratio calibration.
• Not legal for sale or use in California or any state that has adopted California Air Resources Board (CARB) emission standards. Intended for off-road or competition use only in those states.

Features

• Peak dyno-verified gains of 22+ rear-wheel horsepower and 18+ lb-ft of torque over the stock exhaust manifolds - verified through Stainless Works' pre- and post-installation dyno testing on the 5.2L Voodoo engine.
• 1-7/8" diameter primary tubes provide a dramatic improvement in exhaust flow over the stock manifolds, reducing backpressure and enhancing exhaust scavenging throughout the RPM range of the high-revving Voodoo flat-plane V8.
• 3" slip-fit collectors with merge spikes optimize exhaust pulse timing as flows from each primary tube combine, further improving scavenging efficiency and mid-range torque.
• Factory Connect design bolts directly to the factory exhaust slip-fit point - no modification, additional mid-pipe, or custom fabrication required. Retains full compatibility with the stock cat-back or Stainless Works Factory Connect exhaust systems.
• High-flow catalytic converters integrated into the 3" catted lead pipes maintain downstream emissions compliance for the header section while delivering significantly less restriction than the OEM catalysts.
• CNC mandrel-bent primary tubes preserve a consistent tube diameter through every bend, eliminating the flow restrictions and pinch points of OEM manifolds for maximum exhaust gas velocity.
• Fully TIG welded at every joint by skilled fabricators at Stainless Works' Ohio facility - producing leak-free, high-strength connections designed to withstand the extreme thermal cycling of the Voodoo's high-RPM character and track use.
• 3/8" thick laser-cut steel flanges resist warping and heat distortion, providing a flat, repeatable sealing surface at the cylinder head - no gaskets required.
• 304 stainless steel construction resists corrosion, heat oxidation, and road salt exposure - will not red-rust like the cheaper 400-series stainless used by competing header manufacturers.
• Raw/natural mill finish delivers an authentic motorsport aesthetic consistent with the GT350's track-focused character.
• Engineered and manufactured in Ohio, USA by Stainless Works, backed by a limited lifetime warranty on materials and workmanship.

Specifications

• Primary Tube Diameter: 1-7/8" (outside diameter)
• Lead Pipe / Collector Diameter: 3"
• Collector Type: 3" slip-fit with merge spike
• Catalytic Converter: High-Flow (integrated into 3" catted lead pipes)
• Connection Type: Factory Connect (slip-fit to OEM factory exhaust connection point)
• Header Type: Long Tube
• Flange Thickness: 3/8" laser-cut steel
• Material: 304 Stainless Steel
• Finish: Raw / Natural
• Fabrication Method: CNC mandrel bent, fully TIG welded
• Claimed Peak Gain: 22+ RWHP / 18+ lb-ft TQ (Stainless Works dyno tested)
• Tune Required: Yes
• Gaskets Required: No
• CARB Legal: No - not for sale or use in California or CARB-adopting states
• Sold As: Pair
• Country of Manufacture: USA (Ohio)
• Warranty: Limited lifetime on materials and workmanship; 2 years on catalytic converters

Included Components

• 1x Driver side long tube header with 3" catted lead pipe
• 1x Passenger side long tube header with 3" catted lead pipe
• Installation hardware

Product Description

The Stainless Works GT350HCAT is a Factory Connect long tube header system with integrated high-flow catted lead pipes, engineered specifically for the 2015-2020 Ford Mustang Shelby GT350 and GT350R equipped with the 5.2L Voodoo flat-plane crank V8. This is a purpose-built system designed around the unique character of the Voodoo engine - a high-revving, naturally aspirated powerplant with a factory exhaust note already known for its sharp, exotic character. The GT350HCAT amplifies that character while adding meaningful power gains across the RPM range that the stock cast manifolds cannot deliver.

The Factory Connect designation means this system terminates at the factory exhaust slip-fit connection point, making it a direct bolt-in to the stock cat-back exhaust with no additional parts, mid-pipe, or custom work required. It can also be paired with Stainless Works' own Factory Connect cat-back systems for a full-system upgrade. Each header is built from 1-7/8" CNC mandrel-bent 304 stainless steel primary tubes that flow into 3" slip-fit collectors with merge spikes, then into 3" catted lead pipes with integrated high-flow catalytic converters. The 3/8" laser-cut flanges seal against the cylinder heads without gaskets, and every joint is fully TIG welded by skilled fabricators at Stainless Works' Ohio facility. Stainless Works' dyno testing on the Voodoo application has documented peak gains of 22+ rear-wheel horsepower and 18+ lb-ft of torque over the stock manifolds.

The Voodoo engine's flat-plane crankshaft configuration means it produces exhaust pulses in a firing order that naturally benefits more from the scavenging improvements of long tube headers than a cross-plane V8 - making this upgrade particularly well suited to this application. The result is an exhaust note that is substantially louder, sharper, and more race-bred than stock under hard acceleration, with power gains concentrated in the mid-to-upper RPM range where the Voodoo lives. A custom tune is required after installation to recalibrate the ECU's air/fuel and timing maps. This product is not CARB certified and is not legal for street use in California or any state that has adopted California emissions standards. Fitment for the GT350R is confirmed; convertible fitment has not been verified by Stainless Works and should be confirmed before ordering.