If you own a Chrysler A-body from the 1964–1976 era—think Dodge Dart or Plymouth Valiant—you already know these cars are lightweight, nimble, and begging for more power. Swapping in a Mopar performance exhaust system is one of the best upgrades you can make: it unlocks hidden horsepower, transforms the exhaust note into a classic muscle-car growl, and often improves fuel economy. This expanded guide covers everything you need to know about noise, power, cost, and installation so you can choose and install the perfect system for your A-body.

What Exactly Is an A-Body?

Chrysler’s A-body platform launched in 1964 and remained in production through 1976. It underpinned some of the most iconic Mopar nameplates:

  • Dodge Dart (1963–1976)
  • Plymouth Valiant (1960–1976)
  • Plymouth Duster / Dodge Demon / Dodge Sport

These cars shared a unibody structure with a longitudinal engine bay and leaf-spring rear suspension. Their relatively light curb weight (often under 3,200 pounds) made them natural candidates for small-block V-8 swaps and performance exhaust upgrades. Even stock six-cylinder A-bodies benefit from a less restrictive exhaust system.

Why Upgrade to a Mopar Performance Exhaust?

The factory exhaust on a vintage A-body was designed for low cost and quiet operation. A genuine Mopar performance exhaust (or a quality aftermarket equivalent) changes everything:

  • Real Power Gains: A free-flowing exhaust reduces backpressure, allowing the engine to exhale more freely. On a typical small-block V-8, expect 10–20 horsepower and similar torque gains at the rear wheels. Even slant-six engines can pick up 8–12 hp.
  • Better Sound: The exhaust note becomes deeper, throatier, and more aggressive. Mopar performance mufflers like the classic “Sound” or the newer “Touring” lines let you dial in volume from moderate to mean.
  • Weight Reduction: Factory exhaust systems are often made of heavy steel and include bulky mufflers. A modern mandrel-bent, stainless steel system can shed 20–40 pounds off the car.
  • Improved Scavenging: Headers and larger-diameter tubing help pulse waves work together, improving cylinder filling at higher RPMs.
  • Appearance Upgrade: A shiny stainless exhaust with polished tips cleans up the rear underside and gives a custom look at car shows.

Key Choices: Materials, Configuration, and Sound

Not all performance exhaust systems are created equal. Here’s what you need to decide before buying.

Material Options

  • Aluminized Steel: Affordable and corrosion-resistant enough for weekend drivers. Most budget Mopar Performance systems use aluminized steel. Expect a 3–5 year lifespan in salty climates.
  • Stainless Steel (304 or 409): 304 stainless is the gold standard – won’t rust, lasts forever, but costs 2–3× more. 409 stainless is magnetic and more economical but still far more durable than aluminized steel.
  • Mild Steel with Ceramic Coating: A midrange option for headers and downpipes; resists heat and looks great but can chip over time.

Exhaust System Types

  • Axle-Back: Replaces only the mufflers and tailpipes. Easiest install, modest gains (mainly sound).
  • Cat-Back: From the catalytic converter (if equipped) or header collector back. Includes intermediate pipes, mufflers, and tips. Good for street-driver V-8s.
  • Header-Back: Full system from headers to tips. Maximum flow, maximum power. Ideal for built engines.
  • True Dual Exhaust: Two separate pipes from the engine back (requires dual mufflers, often an X-pipe or H-pipe crossover). Adds 15–25 hp over single-exhaust setups.

Muffler Sound Control

Mopar offers several muffler families to match your noise tolerance:

  • Mopar Performance “Sound” Mufflers: Straight-through design, loud and deep – best for track or show cars.
  • Mopar “Touring” Mufflers: Chambered design, moderate volume, zero drone at highway speeds – ideal for daily drivers.
  • Mopar “Sleepy” (OEM-replacement): Near-stock sound but with 20% better flow – perfect for mild builds.

Always check local noise ordinances. A muffler with removable baffles (like Flowmaster or DynoMax) can be tuned later.

Installation: Step-by-Step Guide (DIY-Friendly)

Installing a cat-back or axle-back system on an A-body is a weekend project for someone with basic mechanical skills. A full header-back install adds complexity. Follow these steps for a clean, leak-free job.

Tools & Supplies

  • Floor jack and four jack stands (or a lift)
  • Set of wrenches (metric and SAE, as A-bodies use both)
  • Socket set with extensions
  • Breaker bar and penetrating oil (e.g., PB Blaster)
  • Hacksaw or reciprocating saw (for cutting old pipes if they’re rusted)
  • Exhaust gaskets (manifold-to-header if swapping headers)
  • Anti-seize compound and exhaust sealant
  • Safety glasses and gloves

Preparation

  1. Raise the vehicle safely. Place jack stands under the frame rails (not the axle or rocker panels).
  2. Spray all nuts and bolts with penetrating oil. Let it soak for 30 minutes. Exhaust bolts on A-bodies are notorious for seizing.
  3. Remove old exhaust system. Typically, unbolt the muffler hangers from the rubber isolators, then unbolt the flange at the manifold/header. If you’re swapping from a single-exit system to a dual system, you’ll need to cut or remove the entire pipe.
  4. Inspect hangers and brackets. Replace any that are bent or rusted through.

Installing the New System

  1. Test-fit everything loosely. Hang the new mufflers and pipes with all clamps snug but not tight. This lets you rotate pipes to avoid interference with the rear axle, leaf springs, or floorpan.
  2. Align the tips. Most A-body systems tuck the tailpipes under the rear bumper. Center them visually.
  3. Tighten from front to back. Start at the header/manifold collector and work rearward. Use new gaskets and a smear of exhaust sealant at slip joints.
  4. Check clearance. Wiggle the pipes to ensure at least 1 inch clearance from the gas tank, brake lines, and suspension. A-body rear leaf springs can flex; a rubbing pipe will rattle and possibly melt.
  5. Re-attach hanger isolators. Rubber hangers may need to be cut or drilled for aftermarket pipes.
  6. Start the engine and check for leaks. Run it up to operating temperature. Feel around each joint for escaping air. Tighten clamps as needed.

Tips for Challenging Installations

  • Headers require more work. You’ll likely need to remove the starter and maybe the motor mount bolts to slide header tubes in place. A-body engine bays are tight – consider shorty headers for easier fit.
  • Rusted fasteners are the enemy. If a cross-pipe bolt snaps, use a bolt extractor or drill it out. Replace with stainless hardware.
  • Consider a professional exhaust shop if you need custom bends (e.g., for a dual exhaust setup on a car that originally had a single).

Cost Breakdown: What to Expect

Prices vary widely based on material, brand, and whether you DIY. Use this rough guide for a typical A-body (Dart/Valiant/Duster):

ComponentPrice Range
Mopar Performance axle-back muffler & tailpipes$250–$450
Cat-back system (aluminized) – single exit$350–$600
Cat-back system (stainless) – single exit$600–$1,000
True dual exhaust kit (aluminized)$500–$800
Headers (shorty or long-tube, ceramic coated)$350–$700
Professional installation (labor only)$200–$500

Total for a well-performing setup: Allocating $800–$1,500 for a cat-back system and professional install is realistic. A full header-back dual system can run $1,500–$2,500. Stainless steel adds a premium but pays off with decades of service – especially if you live in a state that uses road salt.

Additional Tuning Tips for Maximum Performance

An exhaust upgrade works best when combined with complementary modifications:

  • Re-jet the carburetor. Less restriction means the engine pulls more air. You may need 2–4 jet sizes richer to maintain the proper air-fuel ratio.
  • Check ignition timing. More airflow may require advancing the timing a few degrees. Use a timing light and experiment (within the engine’s safe limits).
  • Upgrade to an electronic ignition (Mopar Performance or aftermarket) for a stronger spark.
  • Consider a cold-air intake. Pairing a free-flowing exhaust with a high-flow air filter yields the best gains.
  • Use premium fuel if you advance timing significantly.

Noise Regulation and Neighbor-Friendly Options

A muscle car with open headers is loud. Very loud. Many A-body owners want the performance but not a ticket. Some tips:

  • Research your local noise limits (typically 95 dB at 50 feet for street-driven cars).
  • Choose a muffler with adjustable sound (like Speedway Motors “Thrush” with removable baffles).
  • Add a resonator to tone down high-frequency rasp without losing flow.
  • Use a cross-over pipe (X-pipe or H-pipe) to balance sound and reduce drone at highway speeds.

Top Mopar Performance Exhaust Systems for A-Bodies

Here are three proven options that fit common A-body models:

  1. Mopar Performance P4452743 – Cat-Back System (Aluminized)
    Designed for 1967–69 Dart/Demon with small-block V-8. Includes dual mufflers and tailpipes. Sound: aggressive but not obnoxious. Approx. $550.
  2. Flowmaster 17220 – American Thunder Cat-Back
    Universal fit for many A-bodies. 2.5-inch tubing, Delta Flow mufflers. Classic deep tone. 304 stainless. Approx. $700.
  3. Magnafuel 17685 – True Dual Exhaust Kit
    For 1970–76 Duster/Dart with 340/360 engines. Includes X-pipe and mandrel bends. Ceramic-coated headers optional. Approx. $950.

Note: Always verify fitment with your specific year and engine. Some systems may require minor trimming at the rear valance.

Final Recommendations

Installing a Mopar performance exhaust on your A-body is one of the most rewarding projects you can tackle. For the best balance of noise, power, and cost, start with a cat-back stainless steel system from a reputable brand. If your budget allows, add shorty headers and a professional exhaust shop will handle the custom bends. Expect a 15–20 hp gain, a glorious sound, and a car that feels noticeably quicker.

Before you buy, measure your existing tubing diameter and check for rust at the factory flanges – you may need to replace the intermediate pipe too. With careful planning and a weekend’s work, your A-body will sound and perform the way Mopar intended.