Why I Decided to Upgrade My 1970 Plymouth Duster with a Mopar Performance Camshaft Kit

Owning a classic car means constantly balancing originality with performance. My 1970 Plymouth Duster had been a faithful driver for years, but after attending a few Mopar meets and reading countless forum threads, I realized the stock 318 small-block was leaving power on the table. The camshaft is the heart of engine timing—it dictates how long the intake and exhaust valves stay open. A performance cam can transform a lazy cruiser into a responsive street machine. After weeks of comparing specs, I settled on the Mopar Performance Camshaft Kit, which retailed for $1,200 at the time. I wanted to share my real-world experience: the unboxing, installation, driving impressions, and whether it was worth every penny.

In this article, I’ll walk through the entire process—from research to the first cold start—so you can decide if a cam swap is right for your Duster or similar classic Mopar.

Understanding the Role of a Camshaft in Classic Mopars

The camshaft is arguably the most important component for engine breathing. It controls the timing and lift of the intake and exhaust valves. On a stock 1970 Duster 318, the factory camshaft is designed for smooth idle and fuel economy, but it seriously limits horsepower above 4,000 RPM. Upgrading to a performance camshaft like the Mopar Performance unit unlocks the engine’s potential by optimizing the valve events.

Key Benefits of an Aftermarket Camshaft

  • Increased Horsepower and Torque: A performance cam shifts the power band upward, giving you more mid-range and top-end power. I noticed the biggest gains between 2,500 and 5,500 RPM.
  • Improved Throttle Response: The engine feels more eager to rev. The cam’s aggressive lobe profile helps the intake charge fill the cylinders more efficiently.
  • Better Engine Sound: That iconic muscle car lope at idle is a direct result of increased valve overlap. The Mopar cam gives a deep, choppy idle that turns heads.
  • Potential for Future Upgrades: A camshaft lays the foundation for other mods like a better intake, headers, and a free-flowing exhaust.

How I Chose the Mopar Performance Camshaft Kit Over Competitors

The market is full of camshaft options: Comp Cams, Lunati, Edelbrock, and of course Mopar Performance. I chose the factory-direct kit for a few reasons. First, the Mopar Performance line is engineered specifically for Chrysler engines—they understand the nuances of the LA and Magnum families. Second, the kit comes complete with camshaft bearings, lifters, and detailed instructions, which simplifies installation. Third, the price point at $1,200 was competitive. Comparable kits from aftermarket brands often cost the same but may require sourcing separate parts.

If you’re building a high-compression race engine, you might go with a custom grind. But for a daily-driven street Duster that still sees highway miles, the Mopar Performance cam is an excellent balance. I also read multiple threads on For A Bodies Only that confirmed this cam delivers real-world gains without destroying drivability.

Unboxing the Kit: What You Get for $1,200

The kit arrived in a sturdy cardboard box with Mopar branding. Inside, everything was well-protected with foam and bubble wrap. Here’s what was included:

  • Mopar Performance Camshaft – The cam itself is made from billet steel with hardened lobes. The grind number on the end confirmed the specs I ordered: .450 intake / .458 exhaust lift, 276° advertised duration.
  • Camshaft Bearings – Three precision bearings for the engine block journals. These are necessary because the old bearings must be replaced when installing a new cam.
  • Lifters – The kit came with hydraulic flat tappet lifters, pre-soaked in oil. Some kits don’t include lifters, so this saved me $80–100.
  • Installation Instructions – A multi-page booklet with torque specs, timing chain alignment diagrams, and break-in procedures. The instructions were clear for a DIYer with moderate mechanical experience.
  • Mopar Decal – A small touch, but I stuck it on my tool chest. Some people put it on the air cleaner or engine bay.
  • Timing Chain Set – Actually, the kit I purchased included a double-roller timing chain and gears, which is essential for accurate cam timing. Not all kits include this, so confirm when ordering.

Everything looked high quality. No missing parts, no damaged components. I did a quick test fit of the cam in the block before tearing down the engine, just to verify the bearing dimensions.

Installation: A Weekend Project with Rewarding Results

Installing a camshaft is not a beginner-level job. It requires pulling the front of the engine apart—removing the radiator, water pump, harmonic balancer, timing cover, and timing chain. I set aside an entire weekend and worked in a well-lit garage with a good set of tools. If you’re not comfortable with engine internals, having a shop do the install will cost $600–$1,000 in labor. But I enjoy turning wrenches, so I tackled it myself.

Step 1: Preparations and Safety

I disconnected the battery, drained the coolant, and removed the hood for better access. Then I unbolted the accessories: alternator, power steering pump, and air conditioning compressor (my Duster has A/C). After that, I pulled the radiator and fan shroud. This gave me clear access to the timing chain cover.

Step 2: Disassembly of Old Components

With the timing cover off, I rotated the engine to top dead center on cylinder #1. I removed the timing chain and gears, then unbolted the camshaft retainer plate. Before pulling the cam, I removed the distributor, intake manifold, and rocker arms. Then I slid the old camshaft out through the front of the block—it came out smoothly because the bearings were still in decent shape. I also removed the lifters using a magnet; they were worn on the bottom, confirming the upgrade was overdue.

Step 3: Cleaning and New Bearing Installation

I cleaned the engine block thoroughly, especially the bearing journals. I used a bearing tool to press out the old cam bearings and install the new ones. If you don’t have a bearing tool, you can rent one from an auto parts store. The new bearings went in with a little oil, and I verified they were aligned with the oil holes in the block.

Step 4: Installing the New Camshaft

This is the critical part. I coated the cam lobes with high-pressure assembly lube and carefully slid the cam into the block, rotating it slowly to avoid damaging the new bearings. Then I installed the cam retainer plate and torqued it to spec. Next, I installed the new lifters, again using assembly lube on the bottoms. I set the timing chain and gears according to the instruction’s alignment marks, making sure the dots on the crank and cam gears matched. I torqued the cam bolt and crank bolt to factory specs. After that, I reassembled the timing cover, water pump, and all accessories.

Step 5: Prime the Oil System and Set Ignition Timing

Before starting the engine, I used a priming tool to spin the oil pump and make sure oil reached the top end. Then I installed the distributor and set the initial timing to 10° BTDC. I filled the cooling system and checked for leaks.

Total time for the swap was about 12 hours spread over two days, including trips to the hardware store for a few bolts. If you’re organized, you can do it in one long day.

First Start and Break-In Process

The moment of truth. I turned the key and the Duster fired on the third crank—the cam lope was immediate and pronounced. The idle settled at around 900 RPM with a deep rumble. I followed the cam break-in procedure: run the engine at 2,000–2,500 RPM for 20 minutes, varying the speed slightly. This seats the lifters to the cam lobes. I monitored oil pressure (steady at 40 psi hot) and watched for any unusual noises. Everything was smooth.

Driving Impressions: Real-World Performance Gains

After the break-in, I changed the oil and filter (important to do after break-in to remove metal particles). Then I took the Duster for a proper test drive on back roads and the highway. Here’s what changed.

Horsepower and Torque

The difference was dramatic. The stock cam would pull okay to 4,000 RPM then flatten out. With the Mopar Performance cam, the engine pulls hard from 2,500 RPM all the way to 5,500. Passing on the highway is effortless—I can accelerate from 65 to 80 mph without downshifting. The torque increase in the mid-range is especially noticeable; you can feel the car surge forward when you stab the throttle.

Throttle Response

It went from lazy to sharp. The engine responds instantly to pedal input. Part-throttle driving is more fun because you can feel the engine waking up. The cam’s increased overlap helps scavenge exhaust, which improves cylinder filling.

Sound and Character

The exhaust note changed completely. With my Flowmaster mufflers, the idle has a classic muscle car chop. Under acceleration, the exhaust has a crisp bark. At cruise, it’s still civilized enough for daily driving. My neighbors noticed—one commented that the car sounded “meaner.” The Duster went from a comfortable cruiser to an attention-getting street machine.

Downsides to Consider

No upgrade is perfect. Here are the trade-offs I experienced:

  • Increased Idle Noise: The lope is noticeable inside the cabin. If you prefer a quiet ride, this might be too much. I personally love it.
  • Slight Decrease in Fuel Economy: I estimate a drop of 1–2 mpg. The cam is less efficient at low RPM, and my right foot is heavier now because the car is so responsive. If you drive normally, the drop is minimal.
  • Need for Supporting Mods: To fully exploit the cam, you’ll want a four-barrel intake and carburetor upgrade. I already had a Edelbrock Performer intake and 600 cfm carb, which worked well. Without those, the gains would be less.
  • Valve Train Noise: The new lifters tick a little louder than stock, but it’s within normal range for a performance cam. Use a good break-in oil and check lash after 500 miles.

Cost Breakdown: Was $1,200 Worth It?

Let’s look at the numbers. The kit cost $1,200. If you need a shop to install it, add $600–$1,000. I also bought a new harmonic balancer ($80) and a gasket kit ($40). Total outlay: about $1,320. For that money, I gained approximately 30–40 horsepower at the wheels (estimated from dyno charts of similar builds). That’s roughly $33–44 per horsepower, which is excellent value compared to other mods like heads or superchargers.

More importantly, the driving experience is transformed. The Duster is now more enjoyable on twisty back roads, and it’s a riot at stoplight meets. If you’re planning to keep your Mopar for years and want to feel a genuine performance boost, this cam kit is one of the best bang-for-buck upgrades.

Comparing the Mopar Performance Cam to Other Options

I tested a friend’s Duster with a Comp Cams XE268 grind. His car felt similar in the mid-range but had a slightly rougher idle. The Mopar cam seemed to have a broader torque curve. Another buddy used a Lunati Voodoo cam and got excellent top-end power, but his car needed a higher stall converter to launch well. For a street car with an automatic transmission and 3.23 gears, the Mopar Performance cam is a great match. If you have a manual transmission, you might prefer a more aggressive grind.

I recommend checking MotorTrend and Hot Rod Magazine for cam comparison articles—they often dyno test different profiles on small-block Mopars.

Final Verdict and Recommendations

If you own a 1970 Plymouth Duster (or any LA-powered Mopar) and you’re looking for a meaningful performance upgrade without gutting your bank account, the $1,200 Mopar Performance Camshaft Kit is an excellent choice. It delivers on the promises of more power, better sound, and improved throttle response. Installation is challenging but doable for a competent DIYer. Just make sure you budget for a few extra parts and follow the break-in procedure religiously.

My Duster went from a weekend cruiser to a car that truly excites me every time I drive it. The cam upgrade has been the single best modification I’ve made. If you’re on the fence, I say go for it—you won’t regret the lope in your idle.

For more information on camshaft selection, installation tips, and classic Mopar performance, check these out:

Good luck with your build, and enjoy that new cam sound.