Best Cam For 40 Jeep

Selecting a camshaft for a 4.0L Jeep engine involves balancing low-end torque gains with idle quality for daily driving. When you search for the best cam for 40 jeep, you are likely looking for a part that wakes up your Wrangler, Cherokee, or Comanche without ruining its street manners. The 4.0L inline-six is legendary for its reliability, but its stock camshaft leaves power on the table. A good cam can transform your Jeep, giving you more grunt off-road and better passing power on the highway. But with so many options, how do you choose the right one?

This guide will walk you through everything you need to know. We will cover camshaft basics, top cam profiles, installation tips, and tuning advice. By the end, you will know exactly which cam fits your driving style and budget. Let’s get started.

Understanding Camshaft Basics For The 4.0L Jeep

Before we dive into specific cams, you need to understand what a camshaft does. The cam controls when the intake and exhaust valves open and close. This timing directly affects engine power, torque, and idle quality.

For the 4.0L Jeep, the stock cam is designed for smooth idling and decent low-end torque. But it leaves power on the table above 3,000 RPM. Aftermarket cams change the valve timing to shift the power band.

Key Cam Specs To Know

Duration: How long the valve stays open. Measured in degrees of crankshaft rotation. Longer duration shifts power higher in the RPM range.
Lift: How far the valve opens. More lift allows more air into the cylinder, increasing power.
Lobe Separation Angle (LSA): The angle between the intake and exhaust lobes. Tighter LSA (like 110°) gives a choppy idle and more top-end power. Wider LSA (like 114°) smooths the idle and improves vacuum.

For a daily-driven Jeep, you want a cam with moderate duration (around 260-270° advertised), moderate lift (around 0.450-0.480 inches), and a wider LSA (112-114°). This keeps the idle smooth and the vacuum high for power brakes.

Now we get to the main event. The Best Cam For 40 Jeep depends on your specific goals. Are you building a rock crawler that needs instant torque? Or a daily driver that sees highway miles? Here are the top contenders.

1. Comp Cams 68-231-4 (The Daily Driver Champ)

This is arguably the most popular cam for the 4.0L. It offers a great balance of power gains without sacrificing drivability.

Specs: Duration 260° intake / 268° exhaust, Lift 0.450″ intake / 0.458″ exhaust, LSA 112°
Power Gains: 15-20 horsepower and 15-20 lb-ft of torque across the RPM range
Idle Quality: Slightly choppy but very streetable. You will notice a mild lope.
Best For: Daily drivers, mild off-road use, and highway cruising.

This cam works well with stock cylinder heads and intake manifolds. You will need to upgrade the valve springs to handle the higher lift. It also pairs nicely with a cold air intake and a free-flowing exhaust.

2. Mopar Performance P5249464 (The OEM+ Upgrade)

If you want a cam that feels like a factory upgrade, this is it. Mopar designed this cam for the 4.0L to work with stock components.

Specs: Duration 252° intake / 252° exhaust, Lift 0.430″ intake / 0.430″ exhaust, LSA 114°
Power Gains: 10-15 horsepower, mostly in the mid-range
Idle Quality: Near stock. Very smooth, no lope.
Best For: Towing, daily driving, and those who want a hassle-free install.

This cam does not require new valve springs, making it a budget-friendly option. However, the power gains are modest compared to other cams. It is a safe choice for beginners.

3. Crower 50230 (The Torque Monster)

For serious off-roaders who need low-end grunt, the Crower 50230 is hard to beat. It focuses on building torque right off idle.

Specs: Duration 256° intake / 264° exhaust, Lift 0.455″ intake / 0.465″ exhaust, LSA 110°
Power Gains: 20-25 lb-ft of torque from 1,500 to 3,500 RPM
Idle Quality: Noticeably choppy. You will feel the lope at stoplights.
Best For: Rock crawling, mudding, and low-speed trail driving.

The tighter LSA gives it a more aggressive sound and shifts the power band lower. This cam requires upgraded valve springs and a good tune to run properly. It may also cause a slight loss of power above 4,500 RPM.

4. Lunati 10200704 (The High-RPM Performer)

If you want top-end power for highway passing or racing, the Lunati cam delivers. It sacrifices some low-end torque for impressive gains at higher RPMs.

Specs: Duration 270° intake / 278° exhaust, Lift 0.480″ intake / 0.490″ exhaust, LSA 112°
Power Gains: 25-30 horsepower from 3,500 to 5,500 RPM
Idle Quality: Very choppy. Not ideal for daily driving.
Best For: Street performance, drag racing, and aggressive builds.

This cam requires upgraded valve springs, retainers, and possibly pushrods. It also benefits from ported cylinder heads and a larger throttle body. Expect a noticeable loss of low-end torque below 2,500 RPM.

How To Choose The Right Cam For Your Jeep

Picking the right cam comes down to your driving style and engine modifications. Here is a step-by-step guide.

Step 1: Define Your Goals

Daily Driver: Choose a cam with a smooth idle and wide LSA. Comp Cams 68-231-4 is a great choice.
Off-Road / Rock Crawling: Go for a cam with low-end torque and a tighter LSA. Crower 50230 works well.
Highway / Performance: Pick a cam with longer duration and higher lift. Lunati 10200704 is ideal.
Budget Build: The Mopar Performance cam is affordable and easy to install.

Step 2: Assess Your Current Mods

Your cam choice depends on what else you have done to the engine. A cam alone will not give you maximum gains. You need supporting modifications.

Stock Engine: Stick with a mild cam like the Mopar or Comp Cams. They work with stock heads and intake.
Upgraded Intake & Exhaust: You can step up to a more aggressive cam like the Crower or Lunati.
Ported Heads & Bigger Throttle Body: Go for the Lunati cam to take full advantage of the airflow.

Step 3: Consider Your Transmission

Automatic transmissions need good vacuum for proper shifting. Aggressive cams with tight LSA can cause low vacuum, leading to harsh shifts or slipping. If you have an automatic, stick with a cam that has a LSA of 112° or wider.

Manual transmissions are more forgiving. You can run a tighter LSA cam, but you will need to adjust your driving style to keep the engine in the power band.

Installation Guide: Swapping The Cam In Your 4.0L Jeep

Installing a camshaft is a big job, but it is doable at home with the right tools. Here is a simplified overview.

Tools You Will Need

Socket set and wrenches
Torque wrench
Camshaft removal tool (or a long bolt)
Assembly lube
New valve springs (if required)
Gasket set
Timing chain and gears (recommended)

Step-By-Step Installation

Disconnect the battery and drain the coolant and oil.
Remove the radiator, fan, and shroud to access the front of the engine.
Remove the valve cover and intake manifold.
Remove the timing chain cover and timing chain.
Remove the rocker arms and pushrods. Label them for reinstallation.
Remove the camshaft retaining plate and carefully slide the old cam out. Use a removal tool to avoid damaging the bearings.
Lubricate the new cam lobes with assembly lube and slide it in slowly.
Install the new timing chain and gears, aligning the timing marks.
Reinstall the valve train with new valve springs if needed.
Reassemble everything and fill with fresh oil and coolant.
Prime the oil system by cranking the engine with the ignition disabled until oil pressure builds.
Start the engine and check for leaks. Let it idle for 20 minutes to break in the cam.

Important Tips

Always replace the timing chain and gears when swapping cams. They wear out and can cause issues.
Use new valve springs if your cam has higher lift than stock. Stock springs can bind and cause valve float.
Check pushrod length. Some cams require longer or shorter pushrods to achieve proper preload.
Break in the cam properly. Use break-in oil and vary the RPM during the first 20 minutes.

Tuning After The Cam Swap

A cam swap changes the engine’s air/fuel mixture and timing needs. You will need to tune the engine to get the most out of the new cam.

For OBD-I Jeeps (1991-1995)

These engines use a MAP-based system. You can adjust the fuel curve by changing the MAP sensor signal or using an adjustable fuel pressure regulator. A wideband O2 sensor is essential for tuning.

For OBD-II Jeeps (1996-2006)

These engines use a MAF-based system. You will need a custom tune via a programmer like the Superchips Flashpaq or a standalone ECU like the Holley Terminator X. A tune is critical to avoid lean conditions and check engine lights.

Common Tuning Adjustments

Idle Speed: Increase the idle speed to 750-850 RPM to compensate for the cam’s lower vacuum.
Fuel Trim: Adjust the fuel map to match the cam’s airflow characteristics.
Ignition Timing: Advance the timing slightly (2-4 degrees) to improve low-end torque.

Frequently Asked Questions

What Is The Best Cam For A Stock 4.0L Jeep?

For a stock engine, the Comp Cams 68-231-4 is the best choice. It provides noticeable power gains without requiring major modifications. You will need to upgrade the valve springs, but that is a simple job.

Will A Camshaft Hurt My Jeep’s Reliability?

No, a properly installed camshaft will not hurt reliability. In fact, many aftermarket cams are made from better materials than stock. Just make sure to use quality parts and break in the cam correctly.

Do I Need To Upgrade The Valve Springs With A New Cam?

It depends on the cam’s lift. Most aftermarket cams have higher lift than stock, so upgraded springs are recommended. The Mopar cam is an exception—it works with stock springs.

Can I Install A Cam Without Pulling The Engine?

Yes, you can install a cam in the 4.0L Jeep with the engine in the vehicle. You just need to remove the radiator, fan, and timing cover. It is tight, but doable.

How Much Horsepower Does A Cam Add To A 4.0L Jeep?

A cam alone can add 10-30 horsepower, depending on the profile. Combined with other mods like a cold air intake, headers, and a tune, you can see 40-50 horsepower gains.

Final Thoughts On The Best Cam For 40 Jeep

Choosing the best cam for 40 jeep is about matching the cam to your driving needs. For most daily drivers, the Comp Cams 68-231-4 offers the best balance of power and drivability. If you are building a dedicated off-roader, the Crower 50230 will give you the low-end torque you need. And for high-performance builds, the Lunati 10200704 delivers impressive top-end power.

Remember to plan your build carefully. A cam is just one part of the equation. Pair it with good intake, exhaust, and tuning to get the most out of your 4.0L Jeep. With the right setup, you will have a Jeep that is more fun to drive both on and off the road.

Take your time during installation, follow the break-in procedure, and dont skip the tune. Your Jeep will thank you with years of reliable, powerful performance. Happy wrenching!