Swapping out your stock gen 3 hemi camshaft is hands down the best way to wake up that engine and finally get that deep, choppy idle everyone loves. Whether you're driving a Ram 1500 that feels a bit sluggish off the line or a Challenger that needs to back up its aggressive looks, the camshaft is the "brain" of your engine's mechanical operation. It's the difference between a truck that just hauls groceries and one that pulls like a freight train.
The Gen 3 Hemi family—covering everything from the early 5.7L units in the mid-2000s to the modern 6.4L monsters—is a fantastic platform for modifications. But unlike the old-school small blocks where you could just throw any "RV cam" in and call it a day, these modern engines have a few quirks. You've got to navigate things like VVT (Variable Valve Timing), MDS (Multi-Displacement System), and computer tuning requirements. It sounds like a lot, but once you break it down, it's pretty straightforward.
Understanding the VVT Divide
If you're looking for a new gen 3 hemi camshaft, the first thing you need to know is the year of your engine. In the Hemi world, 2009 is the big turning point. Pre-2009 engines (often called "Non-VVT" or "Pre-Eagle" for the 5.7L) are a bit simpler to cam because they don't have the variable timing phasers on the front of the cam. These engines are great for high-RPM builds because the timing is fixed and predictable.
From 2009 onwards, Chrysler introduced the "Eagle" 5.7L and later the "Apache" 6.4L, both of which use Variable Valve Timing. This system is actually pretty cool—it allows the computer to advance or retard the camshaft timing on the fly to give you better low-end torque or more high-end horsepower depending on what you're doing. However, when you put a bigger cam in a VVT engine, you usually have to install a phaser limiter or a lockout kit. This keeps the valves from hitting the pistons when the computer tries to move the cam around too much. It's an extra step, but it's worth it for the massive power gains these newer heads can flow.
Dealing With the MDS Headache
If you own a Hemi, you've probably heard of MDS. It's that system that shuts down four cylinders when you're cruising on the highway to save a bit of fuel. While it sounds good on paper, most enthusiasts hate it. It makes the exhaust sound weird when it kicks in, and more importantly, it requires special "MDS lifters" that are prone to failure.
When you're picking out a gen 3 hemi camshaft, you almost always have to decide if you're doing an MDS delete. Most high-performance cams are "Non-MDS" grinds. This means you'll need to swap out those squishy MDS lifters for solid, non-MDS versions (like the ones from the 6.1L SRT-8) and replace the solenoids with plugs. It adds to the cost of the project, but it's the only way to get a truly aggressive profile and long-term reliability. Trust me, nobody wants to do a cam swap only to have an MDS lifter eat the brand-new lobes six months later.
Choosing Your Cam "Stage"
You'll see cams categorized as Stage 1, Stage 2, or Stage 3. These aren't official industry standards, but they're a good rule of thumb for what you're getting into.
Stage 1: The Daily Driver
A Stage 1 gen 3 hemi camshaft is designed for the guy who wants more power but still needs to pick up the kids or tow a trailer. These cams offer a nice boost in torque across the whole RPM range. The best part? You can usually run these with a stock torque converter. They have a very slight lope, but nothing that's going to make the car shake at a red light.
Stage 2: The Sweet Spot
This is where most people end up. A Stage 2 cam gives you that "muscular" sound and a significant gain in horsepower—usually between 40 and 60 hp depending on other mods. You'll definitely need a custom tune, and if you're driving an automatic, you might want to look into a slightly higher stall torque converter to keep the engine from stalling out when you drop it into gear.
Stage 3 and Beyond: Max Effort
Now we're getting into the "race" territory. A Stage 3 gen 3 hemi camshaft is going to be loud, choppy, and mean. You're going to lose some low-end drivability, and your power band is going to shift way up into the high RPMs. These require upgraded valve springs (which you should probably do anyway), hardened pushrods, and a high-stall converter. It's not the best choice for a heavy truck, but in a stripped-down Challenger? It's a riot.
Don't Forget the Supporting Mods
You can't just slide a gen 3 hemi camshaft into the block and call it a day. These engines are part of a system, and if you change the "brain," you have to upgrade the "muscles" too.
Valve Springs and Pushrods: The stock springs on a 5.7L Hemi aren't really meant for high-lift cams. If you don't upgrade them, you risk coil bind or valve float, both of which lead to expensive engine noises. Most people opt for 6.1L or 6.4L SRT springs because they're affordable and handle higher lift much better. Hardened pushrods are also a smart move because the stock ones can bend under the extra pressure of a performance cam.
The Oil Pump: While you're in there, a lot of guys swap out the stock oil pump for a high-volume unit, like the one from the 6.4L Hellcat. It's cheap insurance. Since you've already got the front of the engine torn apart, it only takes another ten minutes to swap the pump.
Tuning is Mandatory: Don't even think about firing up your car after a cam swap without a custom tune. The factory ECU will have no idea how to handle the extra air coming in, and it'll likely run lean, stall, or throw a hundred codes. You'll need a handheld tuner and a reputable remote tuner (or a local dyno shop) to get the idle and fueling dialed in.
Is It Worth the Effort?
At the end of the day, installing a gen 3 hemi camshaft is a big job. You're looking at pulling the radiator, the grilled, the water pump, and the entire front timing cover. It's a full weekend in the garage with a buddy and a lot of coffee.
But here's the thing: nothing else changes the personality of a Hemi like a cam. When you turn that key for the first time and hear that rhythmic thump-thump-thump of a performance grind, you'll forget all about the bruised knuckles and the money spent. You aren't just gaining horsepower; you're giving the truck its soul back.
Whether you're looking for better towing performance or you want to dominate the local drag strip, the right gen 3 hemi camshaft is out there. Just make sure you do your homework on your specific year and model, don't skimp on the lifters, and always, always get a good tune. Your Hemi will thank you for it by screaming all the way to the redline.