Table of Contents
Introduction to Pypes Challenger Headers
Upgrading your Dodge Challenger’s exhaust system with high-quality aftermarket headers is one of the most effective ways to unlock additional horsepower and torque. Pypes Performance Exhaust has been a trusted name in the muscle car community for decades, offering stainless steel and mild steel headers specifically designed for Challenger models. Their header systems are engineered to reduce backpressure, improve scavenging, and deliver a deeper, more aggressive exhaust note.
This guide provides a comprehensive, step-by-step approach to installing Pypes Challenger headers. Whether you’re a seasoned DIY enthusiast or a first-time installer, following these instructions will help you achieve a leak-free installation that maximizes performance gains. The process typically takes 4 to 8 hours, depending on your experience level and the specific Challenger model (R/T, SRT, GT, or V6 variants).
Tools and Materials Needed
Before raising your vehicle, gather all the necessary tools and replacement parts. Having everything within arm’s reach will prevent unnecessary breaks and reduce the risk of mistakes.
- Socket and ratchet set – Metric and SAE sizes; 10mm, 13mm, 15mm, 18mm are common for header bolts and exhaust flanges.
- Torque wrench – ½-inch drive rated up to 100 ft-lbs for precise tightening of header bolts and collector nuts.
- Floor jack and four jack stands – Always support the vehicle on solid, level ground.
- Header gaskets – Use the gaskets included with your Pypes headers or upgrade to high-quality MLS (multi-layer steel) gaskets.
- Header bolts or studs – Many header kits include new hardware; if not, purchase a grade‑8 fastener set.
- Penetrating oil – Spray on stubborn nuts and bolts 24 hours before starting.
- Safety glasses and mechanic’s gloves – Essential for protection from debris and sharp edges.
- Oxygen sensor socket – If your vehicle requires removing factory O2 sensors.
- Exhaust gasket sealer (optional) – For extra assurance against leaks at the head ports.
- Shop towels and wire brush – For cleaning mating surfaces.
Safety Precautions and Vehicle Preparation
A safe, organized workspace is critical. Working under a vehicle with inadequate support can lead to serious injury.
- Park on a flat, dry surface. Concrete or asphalt is ideal; avoid gravel or dirt.
- Engage the parking brake. Chock the rear wheels for added stability.
- Disconnect the negative battery terminal. This prevents accidental shorts when working near the starter or electrical components.
- Raise the vehicle. Use a floor jack to lift the front end high enough to work comfortably. Place jack stands under the frame pinch welds or designated lift points. Never rely solely on a hydraulic jack.
- Allow the engine to cool completely. Hot exhaust components can burn severely and make bolts harder to remove.
Removing the Factory Exhaust Manifolds
With the vehicle safely elevated, you can begin removing the stock exhaust manifolds. The OEM cast-iron manifolds are heavy and restrictive; removing them gives you access to the cylinder head ports.
Step 1 – Remove Obstructions
- On most Challenger models, you’ll need to remove the front wheel and inner fender liner to access the lower manifold bolts.
- Detach the air intake tube and, if necessary, the battery tray on the passenger side for additional clearance.
- If your engine has spark plug wires routed near the manifolds, carefully unclip and move them aside.
Step 2 – Unbolt the Manifolds
- Working from underneath and above, loosen all manifold-to-head bolts. Use penetrating oil on any that appear rusted.
- Remove the bolts and carefully lower each manifold. You may need to wiggle it past the steering shaft or frame rail. Do not force it.
- Disconnect the exhaust crossover pipes or catalytic converters from the manifolds using the flange bolts.
- If your vehicle has oxygen sensors in the manifolds, unscrew them with an O2 sensor socket before fully removing the manifold.
Step 3 – Clean the Mating Surfaces
Use a wire brush and rags to remove old gasket material, carbon deposits, and rust from the cylinder head surfaces. Any leftover debris will cause exhaust leaks. Also clean the head bolt holes to ensure threads accept the new hardware smoothly.
Installing the Pypes Headers
Now the real transformation begins. Take your time to position the headers carefully; rushing can cause clearance issues or damage to the header gaskets.
Step 1 – Install Header Gaskets
- Apply a thin, even coat of high-temp sealant to both sides of the gasket (if using a gasket sealer). Many builders prefer dry MLS gaskets – follow the manufacturer’s advice.
- Place the gasket over the head studs or into the ports, aligning the bolt holes precisely.
Step 2 – Position the New Header
- Slide the header into place from either above or below, depending on your Challenger’s chassis clearance. For many SRT and R/T models, passenger-side headers go in from under the car, while driver-side can be inserted from above after removing the dipstick tube and steering shaft clamp.
- Guide the header ports over the studs (or align with bolt holes) and gently push the header against the gasket. Do not force the header into position; if it doesn’t seat easily, check for obstructions.
- Install the supplied header bolts or studs finger-tight. Start with the center bolts, then work outward.
Step 3 – Torque to Specification
Using a torque wrench, tighten each header bolt gradually in a crisscross pattern. The typical torque specification for Pypes headers on Chrysler V8s is 35–45 ft-lbs for the 6.4L Hemi and 30–40 ft-lbs for the 5.7L Hemi. Always verify with the instructions included in your kit. Over-torquing can warp the flange or strip the head threads.
Step 4 – Connect the Exhaust System
- Reattach the downpipes or catalytic converter flanges to the header collectors using the supplied gasket and bolts. Torque these to manufacturer specs (often 35–40 ft-lbs).
- If you have removed the O2 sensors, reinstall them into the bungs provided on the headers. Use anti-seize compound on the threads to simplify future removal.
- Double-check that all V-band clamps or springs (if used) are seated correctly.
Reassembling Removed Components
Once both headers are bolted in and the exhaust is reconnected, reverse the removal steps.
- Reinstall the inner fender liners and front wheels (if removed).
- Reattach the battery tray and air intake tube.
- Route spark plug wires away from the hot header tubes using heat-resistant separators if needed.
- Reconnect the negative battery terminal.
- Lower the vehicle from the jack stands.
Testing and Post-Installation Checks
A proper test ensures the headers are leak-free and the engine runs optimally.
Cold Start Inspection
- Start the engine and let it idle for 2–3 minutes. Listen for ticking or hissing sounds, especially at the cylinder head flanges and collector connections. A minor tick may seal after heat cycling, but large leaks require immediate retorquing.
- While the engine is cold, run your hand (using a glove for safety) near each port to feel for puffs of exhaust gas. Alternatively, use soapy water in a spray bottle – bubbles indicate leaks.
- If you detect a leak, allow the engine to cool, then retorque the bolts. Sometimes a second retorque after a few heat cycles is necessary.
Test Drive and Performance Verification
- Take the vehicle for a 15–20 minute test drive that includes both city and highway speeds. Pay attention to acceleration response, especially at mid-range RPMs.
- Monitor the check engine light. If it illuminates, scan the code – a lean code may indicate a pre-cat O2 sensor reading due to increased exhaust flow from the headers. A quick relearn cycle or O2 spacer may be needed.
- Note any new rattles or vibrations; check header clearance against the steering shaft, frame rail, and engine mount.
Tuning Considerations After Header Installation
Adding free-flowing headers increases the engine’s ability to expel exhaust gases, which often shifts the air/fuel ratio leaner. While modern Hemi engines can adapt to a degree through the ECU’s short-term fuel trims, a professional dyno tune or handheld tuner calibration is highly recommended to fully exploit the horsepower gains (typically 15–25 hp on 5.7L and 6.4L engines).
- Re-calibrate fuel trims – Tuners can adjust the VE table and ignition timing for the increased exhaust flow.
- O2 sensor spacers – If you encounter a P0420 catalyst efficiency code, install spark plug non-foulers with a drill modification to push the O2 sensor slightly out of the direct exhaust stream.
- Cold air intake pairing – Headers work synergistically with a high-flow intake. Consider upgrading both together.
Maintenance and Longevity Tips
Pypes headers are built to last, but proper care extends their life and keeps them performing.
- Monitor bolts after the first 500 miles. Heat cycles can cause settling. Check torque on all header bolts and collector fasteners.
- Use anti-seize on all bolts – This prevents galling and makes future removal easier.
- Inspect gaskets annually – If you notice increased exhaust noise, recheck gasket condition. MLS gaskets often last 80,000+ miles, but they can develop leaks if bolts loosen.
- Keep the headers clean – If your Challenger sees winter road salt, consider ceramic coating or stainless steel headers. Pypes offers both material options; stainless is more corrosion-resistant.
Common Installation Challenges and Solutions
Even experienced mechanics run into obstacles. Here are typical issues with Challenger header installations and how to avoid them.