Upgrading to a Mopar 340 Cold Air Intake is one of the most effective bolt-on modifications you can make to unlock additional horsepower from your Chrysler 340 V8 engine. By replacing the restrictive factory air box with a free-flowing, low-restriction intake system, you allow cooler, denser air to reach the cylinders—resulting in a measurable gain of 15+ horsepower at the wheels. This guide provides a comprehensive, step-by-step installation process so you can complete the upgrade in your own garage with basic hand tools.

Why a Cold Air Intake Matters for the Mopar 340

The Chrysler 340 cubic-inch small block, produced from 1968 to 1973, is legendary for its high-revving capability and torque. However, the factory air intake system was designed for quiet operation and emissions compliance—not peak performance. A cold air intake like the Mopar 340 system relocates the air filter away from the engine’s radiant heat, pulls in ambient air from outside the engine bay, and uses a smoother, larger-diameter tube to reduce air restriction. The result is a more efficient combustion cycle that can translate to 15–20 additional horsepower and improved throttle response.

This kit is specifically engineered for Mopar vehicles equipped with the 340 engine, including the 1970 Dodge Challenger, Plymouth Barracuda, and Chrysler Dart Swinger, among others. Proper installation not only maximizes power gains but also ensures a trouble-free, leak-free system that passes visual inspections and maintains drivability. Let’s walk through the process from beginning to end.

Tools and Materials You Will Need

Before you start, gather everything required to avoid interruptions. Having the correct tools on hand will make each step cleaner and safer.

  • Mopar 340 Cold Air Intake Kit (genuine Mopar part or high-quality aftermarket replacement). Verify it includes the air box, filter, intake tube, clamps, gaskets, and mounting hardware.
  • Socket wrench set with 3/8-inch drive, plus extensions for hard-to-reach fasteners
  • Flathead screwdriver (medium size) to release wire clips and pry loose components
  • Phillips screwdriver for any plastic retainers or sensor connectors
  • Torque wrench (inch-pound range) to tighten clamps and bolts to factory specifications
  • Rubber gloves and shop towels to keep hands clean and wipe away dirt
  • Safety glasses to protect eyes from debris and grease
  • Jack and jack stands (if you need to remove inner fender splash shields or access lower mounting points)
  • Dielectric grease for weatherproofing electrical connectors
  • Penetrating oil (e.g., WD-40 or PB Blaster) to loosen stubborn bolts

Preparation: Set Up Your Workspace and Vehicle

Choose a flat, well-lit area with good ventilation. If possible, work indoors or on a dry, level surface. Allow the engine to cool completely—running or hot components can cause burns. Disconnect the battery (see Step 1) before touching any electrical connections near the intake.

Inspect the kit packaging to confirm all parts are present. Lay them out in order of installation. Review the manufacturer’s instructions (if included) alongside this guide. Some Mopar 340 cold air kits require minor trimming of inner fender liners or removal of a plastic resonator; verify fitment for your specific vehicle year and model before proceeding.

Step 1: Disconnect the Battery

Disconnecting the negative battery terminal is a critical safety step. It prevents accidental electrical shorts while you unplug the Mass Airflow (MAF) sensor, IAT (Intake Air Temperature) sensor, or any other wiring near the intake. Use a 10mm socket or wrench to loosen the cable clamp on the negative (–) post, then wiggle the cable free. Tuck the cable away so it cannot accidentally contact the terminal.

Pro Tip: If your vehicle has an aftermarket stereo or ECU memory device, consider using a memory saver to preserve settings. Otherwise, be prepared to reset your radio presets and clock after reconnecting the battery.

Step 2: Remove the Factory Air Intake System

With the battery disconnected, proceed to remove the stock intake components. Work methodically and keep track of all hardware.

2.1 Disconnect Sensor Wiring

Locate the Mass Airflow (MAF) sensor mounted on the factory intake tube. Press the tab on the connector and pull it free. Do not yank the wires. If the connector is stuck, use a flathead screwdriver to gently pry the latch. Next, disconnect the Intake Air Temperature (IAT) sensor if it is integrated into the factory air box. Note: Some Mopar 340 models do not have an IAT sensor—refer to your vehicle’s service manual.

2.2 Unfasten the Air Box and Intake Tube

Using a socket wrench or screwdriver, remove the screws, bolts, or spring clamps that secure the air filter housing to the inner fender and to the throttle body. Typically, there are two or three bolts holding the air box in place, plus a large rubber coupler at the throttle body. Loosen the coupler clamp and slide the tube free. Lift the air box assembly away from the engine bay. Set aside the factory parts—you may wish to keep them as a backup.

2.3 Clean the Throttle Body Opening

With the intake tube removed, inspect the throttle body bore for dirt and carbon deposits. Use a throttle body cleaner and a clean rag to wipe the inside of the bore. Do not scrub the throttle plate itself too aggressively. A clean surface ensures the new gasket seals properly and reduces the chance of an air leak.

Step 3: Install the Mopar 340 Cold Air Intake

Now you’re ready to mount the new system. Follow these sub-steps carefully.

3.1 Position the Air Box

Place the new cold air intake box into the original location or the recommended mounting area (typically in front of the radiator support or inside the driver-side inner fender, depending on the kit). The box should fit snugly and not contact any moving parts. Use the supplied rubber grommets and bolts to secure it. Some kits include a bracket that bolts to the engine block or chassis—tighten these to the manufacturer’s torque spec (often around 60 inch-pounds).

3.2 Install the Air Filter

Slide the provided high-flow air filter into the box. Most Mopar 340 kits use a conical or panel filter with a reusable cotton gauze element. Ensure the filter seats properly against the box’s sealing rim. If the kit uses a pre-oiled filter, tap it lightly to distribute oil evenly. Overtightening the filter retaining clamp can distort the sealing ring—just snug enough to prevent air bypass.

3.3 Attach the Intake Tube

Connect the intake tube from the air box to the throttle body. Slide the silicone couplers onto the tube ends, then slip them onto the throttle body neck and air box outlet. Use the supplied T-bolt clamps to secure each connection. Position the clamps so the bolt heads are accessible for tightening.

Critical torque: Tighten coupler clamps to 30–40 inch-pounds (or per kit instructions). Over-torquing can crack the plastic tube or damage the silicone. Use a torque wrench for consistency.

3.4 Reconnect Sensors

Plug the MAF sensor into the new intake tube. The sensor should fit into a designated boss or mounting flange. Many Mopar 340 cold air intakes relocate the MAF sensor to the intake tube itself. Secure it with the supplied screws (typically small Phillips). Then reconnect the wiring harness clip. Apply a thin layer of dielectric grease to the connector pins to prevent moisture intrusion.

If your vehicle has an IAT sensor, install it in the provided grommet on the intake tube. Route the wiring away from the exhaust manifold and sharp edges.

Step 4: Reconnect the Battery

Reattach the negative battery cable. Tighten the clamp securely. Now is the time to let the ECU relearn its idle and fuel trims. With the engine off, turn the ignition key to the “ON” position (without starting) for 10 seconds, then turn it off. This primes the fuel system and helps the ECU recognize the new intake. Then start the engine and let it idle for 2–3 minutes without touching the throttle. This idle reset allows the computer to adjust to the increased airflow.

Note: If you disconnected the battery for an extended period, the check engine light may illuminate briefly while the system recalibrates. This is normal and should clear after one drive cycle.

Step 5: Test the Installation

Verifying the install is crucial for both performance and safety. Follow this checklist:

  • Listen for air leaks: With the engine idling, place your hand over the couplers and joints. A whistling or hissing sound indicates an unsealed connection. Tighten clamps as needed.
  • Check for loose hardware: Re-torque all bolts and clamps after 50 miles of driving. Thermal cycling can loosen fasteners initially.
  • Monitor idle quality: The engine should idle smoothly (on a 340, typically 650–800 rpm). If it stumbles or stalls, check for post-installation vacuum leaks or a disconnected sensor.
  • Take a test drive: Accelerate gently to mid-range RPM (2,500–4,000) and feel for a stronger pull. The cold air intake should produce a deeper intake roar. Do a wide-open throttle run on a safe road to confirm the horsepower gain feels genuine.
  • Inspect after a short drive: Let the engine cool and recheck all clamps and filter retainers. Look for any signs of rubbing against hoses or fan shrouds.

Performance Gains and What to Expect

With a successful installation, the Mopar 340 cold air intake delivers a 15+ horsepower increase, often accompanied by a 10–15 ft-lb torque gain in the midrange. The intake noise becomes more aggressive, especially above 3,500 rpm. Fuel economy may improve slightly if you keep your foot steady, but the primary benefit is power on demand. For maximum gains, combine this intake with a free-flowing exhaust system and a tuned carburetor or EFI calibration.

Remember that ambient temperature affects performance—the true cold air benefit shines on cooler days below 80°F. The system pulls denser air from outside the engine bay, which reduces the risk of engine knock (detonation) when running pump gas.

Maintenance Tips for Long-Term Performance

To keep your Mopar 340 cold air intake delivering optimal airflow, follow these simple practices:

  • Clean the air filter every 12,000 miles or more frequently if you drive on dusty roads. Use a dedicated cleaning kit (available from K&N or aFe Power). Do not over-oil after cleaning.
  • Inspect couplers and clamps annually. Rubber and silicone can harden over time. Replace any cracked couplers.
  • Check the MAF sensor element. Some intake oils can contaminate the sensor. If you notice drivability issues after cleaning the filter, clean the MAF sensor with a dedicated MAF cleaner spray.
  • Avoid water ingestion. The Mopar 340 intake is not designed for deep water crossings. If you drive through puddles, consider a hydrophobic filter wrap.

Common Questions and Troubleshooting

Will this void my warranty?

If your vehicle is still under factory warranty, installing a cold air intake may void coverage for related powertrain components. However, the Magnuson-Moss Warranty Act protects you if the intake does not cause the failure. For classic Mopar cars, warranty is not a concern.

Why didn’t I get a check engine light?

That’s a good sign. The Mopar 340 kit is designed to maintain proper air-fuel ratios without triggering diagnostic trouble codes. If you do see a code (e.g., P0171 or P0172), check for vacuum leaks or a faulty MAF sensor.

Can I install this without removing the radiator or fan?

Yes—most Mopar 340 cold air intakes fit without major disassembly. You may need to tilt the air box to slide it past the alternator or power steering reservoir. If space is very tight, use a jack to slightly lift the engine (after removing the fan shroud) to gain clearance.

Final Thoughts

Installing a Mopar 340 Cold Air Intake is a rewarding Saturday project that yields immediate, seat-of-the-pants results. By following this step-by-step guide, you’ve upgraded your classic Mopar’s breathing and unlocked a solid 15+ horsepower gain. The process is straightforward with common tools, and the finished product looks professional under the hood.

For additional reference, consult the Mopar Performance Parts website for official kit documentation. You can also find installation videos and owner reviews on Mopar enthusiast forums and part-specific details at Summit Racing Equipment.

Remember to re-torque all connections after the first heat cycle, and enjoy the crisp throttle response that only a cold air intake can provide. Drive safely, and keep the rubber side down.