Mopar 360 Performance Boost: How a $1,200 Cam Swap Can Add 50 Hp

Mopar 360 Performance: Why the 5.9L V8 Deserves a Cam Upgrade

The Mopar 360, a 5.9-liter small-block V8 that powered countless Dodge and Plymouth vehicles from the early 1970s through the late 1980s, has earned a reputation for bulletproof reliability and satisfying low-end torque. Its cast-iron block and heads, combined with a stout bottom end, make it an excellent candidate for performance modifications. While its factory output was adequate for its era, today’s enthusiasts demand more. Among the most impactful and cost-effective upgrades is a camshaft swap. For roughly $1,200 in parts and careful DIY labor, you can unlock an additional 50 horsepower and transform the engine’s character. This article breaks down exactly what a cam swap involves, how to choose the right cam, the installation procedure, and the real-world gains you can expect.

The Mopar 360 Engine: A Brief Overview

Introduced in the early 1970s, the Mopar 360 evolved from the earlier 340 and 318 LA small-block families. It shares the same external dimensions and bellhousing pattern, but with a larger 4.00-inch bore and 3.58-inch stroke, it delivers a displacement of 360 cubic inches (5.9 liters). The engine was used in passenger cars like the Dodge Dart, Plymouth Duster, and Chrysler Cordoba, as well as in trucks, vans, and motorhomes. Its cast-iron heads typically feature 1.88-inch intake and 1.60-inch exhaust valves, and compression ratios varied from 8.4:1 to 9.5:1 depending on the application. The camshaft in stock form is a mild grind, designed for smooth idle and fuel economy, not peak power.

Despite its age, aftermarket support for the Mopar 360 is strong. Companies like Comp Cams, Lunati, and Howards Cams offer numerous grind profiles that work with the factory valvetrain layout. The key to a successful swap is selecting a cam that matches your vehicle’s intended use, whether it’s a street cruiser, a weekend drag racer, or a daily driver that needs to maintain some level of driveability.

Why a Camshaft Swap Yields 50 HP

The camshaft dictates exactly when the intake and exhaust valves open and close relative to crankshaft position. A performance cam increases valve lift (how far the valve opens) and duration (how many degrees of crankshaft rotation the valve stays open). This allows more air-fuel mixture into the cylinder and expels exhaust gases more efficiently. The result is a higher volumetric efficiency, which translates directly to horsepower and torque gains.

For the Mopar 360, a mild performance cam—such as a 270- or 280-degree duration grind with approximately 0.450 to 0.480 inches of lift—can add 40 to 60 horsepower at the flywheel, with the best results often coming at higher RPM (3500–5500). The $1,200 budget covers not only the camshaft but also the necessary supporting parts: valve springs, timing chain, gaskets, and often new lifters. Since the Mopar 360 uses a flat-tappet lifter design (hydraulic or mechanical), you must choose the correct lifter type and ensure proper break-in.

Component Breakdown: What Your $1,200 Buys

Performance Camshaft: $250–$400. Choose a name-brand grind tailored to your goals.
Valve Springs: $80–$150. Stiffer springs are necessary to control the higher lift and prevent valve float.
Timing Chain and Gear Set: $50–$100. Replace the old nylon-tooth timing set with a quality double-roller chain.
Gaskets and Seals: $50–$80. Includes intake manifold gaskets, timing cover gasket, valve cover gaskets.
Lifters: $60–$100. New hydraulic flat-tappet lifters (avoid reusing old ones).
Pushrods: $20–$40. Check length: performance cams often require longer or shorter pushrods.
Optional: Rocker Arms: $100–$200. Stock stamped rockers may work, but adjustable rockers allow precise geometry.

Total parts cost generally falls between $610 and $1,070, leaving $130 to $590 for incidental items like thread locker, assembly lube, and a shop manual.

Selecting the Right Cam for Your Mopar 360

Choosing a cam involves trade-offs. A cam with more duration and lift will increase peak power but shift the powerband upward, hurting low-end torque and idle quality. For a street-driven Mopar 360, a 224–230 degrees duration at 0.050-inch lift on the intake side, with 0.450–0.480-inch lift, works well. This range provides a noticeable lope at idle while maintaining enough vacuum for power brakes and street manners.

Here is a comparison of popular cam choices for the 360.

Factors to Consider

Vehicle Use: Daily driver with automatic transmission and a 2.5–3.0:1 rear gear? Choose a shorter duration cam. Weekend track car with a manual transmission and 3.7:1 or steeper gears? A larger cam will work.
Compression Ratio: Your 360’s factory compression ratio is likely 8.4:1 or 8.7:1. A cam with too much duration will bleed off cylinder pressure and reduce torque. Choose a cam with at least 110-degree lobe separation to preserve low-end.
Converter Stall Speed: If you have an automatic transmission, you may need a higher stall torque converter (around 2,000–2,500 RPM) to keep the engine in the cam’s power band.
Valve-to-Piston Clearance: Always check. With a moderate cam and factory pistons, clearance is usually fine, but measure to be safe.
Exhaust System: Stock exhaust manifolds are restrictive. A cam swap is most effective when paired with headers and a free-flowing exhaust.

The Cam Swap Installation Process

Performing a cam swap on a Mopar 360 is a weekend-level project for an experienced DIYer. You will need basic mechanic tools, a timing set tool, a degree wheel, and a dial indicator to verify cam timing. Below is the generalized process.

Preparation and Safety

Disconnect the battery and drain the coolant. If the engine is in the vehicle, remove the radiator, fan, and shroud for access.
Remove the intake manifold, valve covers, rocker arms, and pushrods. Replace the intake manifold gaskets.
Remove the water pump and timing cover. Drain the engine oil (oil pan may be removed if needed).
Rotate the crankshaft to top dead center (TDC) on cylinder #1. Mark the timing chain position.

Step-by-Step Cam Removal and Installation

Remove the old camshaft: After removing the timing chain and gear, pull the distributor, remove the camshaft retainer plate, and carefully slide the old cam out of the block. Support the cam lobes to avoid damaging bearings.
Inspect the block and cam bearings: If the bearings are scored or worn, replace them (requires special tools). Apply assembly lube to new bearings.
Install new lifters: Liberally coat each lifter and the cam lobes with cam break-in lube. Install lifters into their bores (they must be indexed correctly).
Install new camshaft: Slide the cam in slowly, rotating it to align with bearings. Install the cam retainer plate with new bolts.
Set timing: Install the new timing set aligning the marks according to the manufacturer’s instructions. Use a degree wheel and dial indicator to confirm the intake centerline. If necessary, use offset crank keys or cam bushings to adjust.
Reassemble: Install timing cover, water pump, pushrods, rocker arms (adjust if adjustable), and valve covers. Reinstall intake manifold with new gaskets.
Initial start and break-in: Use high-zinc break-in oil. Start the engine and immediately bring RPM to 2,000–3,000 and hold for 20 minutes. Do not let it idle. This seats the lifters and cam lobes. After break-in, change oil and filter.

Common Pitfalls

Binding Pushrods: Check clearance between pushrods and cylinder head pushrod holes. Some cams require shorter pushrods.
Valve Spring Coil Bind: Always measure installed height and coil bind clearance after installing new springs.
Incorrect Cam Timing: A few degrees off with a performance cam can cause power loss or detonation. Always degree the cam.
Flat Lifter During Break-In: Use proper break-in procedures and never let the engine idle below 2,000 RPM for the first 20 minutes. Use a quality break-in oil.

Expected Performance Gains and Driving Experience

After a proper cam swap with supporting mods, a Mopar 360 that made 180–200 hp at the flywheel stock (gross or net depending on year) can climb to 230–260 hp, with torque improvements of 30–50 lb-ft in the midrange. That extra 50 hp is easily felt: the engine will pull harder from 2,500 to 5,500 RPM, and throttle response sharpens. The idle will develop a lumpy, aggressive note that announces the engine’s newfound personality.

However, keep in mind that driveability changes: manifold vacuum may drop to 12–14 inHg, requiring a tune for the carburetor or fuel injection system. The brake booster may need a vacuum reservoir. You may also need to recurve the distributor (advance timing) to optimize performance. These adjustments are part of the tuning process.

Beyond the Cam: Complementary Upgrades

A cam swap is most effective when paired with other enhancements. Consider these upgrades to fully realize the potential:

Heads: Ported or aftermarket aluminum heads can add another 30–50 hp. Edelbrock E-Street heads are a popular choice for the 360.
Intake and Carburetor: A dual-plane intake manifold (like Edelbrock Performer) and a 600–750 cfm carburetor match the cam’s airflow needs.
Exhaust: Headers (1-5/8 inch primary tubes) and a 2.5-inch dual exhaust system reduce backpressure.
Ignition: An aftermarket electronic ignition kit (e.g., MSD or Mopar Performance) ensures reliable spark at higher RPM.

These additions push the total investment toward $2,500–$3,000 but can yield 80–120 hp over stock.

Cost-Benefit Analysis: Is $1,200 Worth 50 HP?

For a muscle car or truck owner seeking a noticeable power increase without breaking the bank, a cam swap is hard to beat. The $1,200 parts cost is about $24 per horsepower, which is far cheaper than forced induction or a full engine rebuild. Labor can be saved by doing the work yourself; a shop would charge $600–$1,000 in labor, doubling the total. Even so, $2,200 for a 50-hp gain is still economical compared to alternatives like a stroker kit ($3,500+ for 50-70 hp) or a supercharger ($4,000+ for 100 hp).

Comparison with Other Upgrades for the Mopar 360

Upgrade	Estimated HP Gain	Cost (Parts Only)	Cost per HP
Cam Swap	50	$1,200	$24
Headers + Exhaust	15–25	$600–$900	$36
Aluminum Heads	40–60	$1,500–$2,000	$33
Intake + Carburetor	15–25	$500–$700	$35
Ignition System	5–10	$300–$500	$60

Note: Gains are cumulative. Combining a cam with heads and exhaust yields more than the sum of individual parts due to improved airflow matching.

Conclusion

A camshaft swap remains one of the smartest modifications for the Mopar 360 engine. For about $1,200 in quality parts and a weekend of careful labor, you can unlock a reliable 50 horsepower gain that transforms the engine’s character. The key is selecting the right cam for your driving style, installing it correctly with new lifters and timing set, and paying attention to break-in and tuning. While the swap requires some mechanical confidence, the reward is a more exhilarating driving experience—stronger pull, a loping idle, and the satisfaction of knowing you made the Mopar 360 perform exactly as it should have from the factory. Whether you’re cruising a classic Dodge Dart or restoring a Ramcharger, this affordable power upgrade puts the thrill back on the road.