The 5.7 HEMI is a great motor, but it usually lacks adequate horsepower from the factory. Fair enough, thinking about how the big 5.7L V8 only produces around 400 hp. In spite of this, the 345 HEMI has a great deal of potential after receiving a few bolt-on improvements. Upgrading to a 5.7 HEMI intake manifold is one of the better modifications you can do. Gains in power, benefits, expenses, and more are discussed in this article for modifications to the intake manifold of a 5.7L HEMI V8 engine.
5.7 HEMI Intake Manifold Benefits
Benefits of a 5.7 HEMI intake manifold upgrade can vary depending on goals and the specific manifold in question. Nonetheless, a few potential benefits of 5.7L HEMi intake upgrades include:
- 5-10whp peak gains
- 10-20whp & 15-30wtq midrange gains
- Added strength
- Improved sounds
- Better looking engine bay
Intake manifolds can have a major impact on power improvements. Therefore, we’ll talk about horsepower gains in the next section and then return to that topic when we talk about individual manifolds.
The 5.7 HEMI V8 comes with a plastic factory manifold. The manifold for a 6.1L HEMI engine, and many aftermarket alternatives, is made of aluminum. In a naturally aspirated engine, a plastic manifold is adequate. If you’re considering boost, though, you’ll probably want something a little more powerful and fluid.
Modifying the 5.7 HEMI intake manifold is another way to enhance engine sounds and make the engine compartment appear better. But that’s all relative, so it might not help anyone.
Dodge 5.7L V8 Manifold HP Gains
In most cases, upgrading the intake manifold on a 5.7 HEMI does not result in noticeable increases in peak output. Depending on the modifications made to the engine and the tuning used, you could see an increase of 5-10whp at the upper end. Intake manifolds aren’t a waste of money, even if the peak increases aren’t impressive. Manifold enhancements are most useful towards the middle of a vehicle’s rev range.
Midrange improvements of 10-20 horsepower and 15-30 lb-ft of torque have been reported when installing a 6.4L HEMI manifold. Those are great power increases, especially as most driving is done there. Adding an intake manifold is money well spent because you will noticeably increase your vehicle’s performance.
However, in most cases, we believe that additional power upgrades, such as a tune, headers, cams, etc., are a better place to begin. All these upgrades have the potential to increase not only your vehicle’s peak power and torque, but also its midrange and top-end performance. Our research revealed that an intake manifold wasn’t quite as effective as the other enhancements we considered for the 5.7 HEMI, and thus it didn’t make the cut.
Despite this, you should still upgrade the 345 HEMI intake manifold. A manifold is essential if you want to get the most out of your NA engine. To put it simply, an intake manifold isn’t the first performance part you should upgrade.
The estimated power increases above for the 6.4L HEMI manifold swap are only estimates. It’s possible that certain manifolds sacrifice some low-end power in exchange for more substantial increases at higher RPM. When we get to the part when we talk about specific 5.7 HEMI intake manifolds, we’ll go into detail.
Best 5.7 HEMI Intake Manifold Upgrades
Now that we’ve covered the whys and whatfors, we can dive into the top 5.7 HEMI intake manifold mods. This is not meant to be an all-inclusive list. We can’t possibly go over every possible upgrade here.
Instead, we’ll look at a few of the most popular and beneficial 5.7 HEMI upgrades on the market today. Know what you want to accomplish before settling on an intake manifold. So, without further ado, let’s get into a discussion of the top HEMI manifold upgrades.
1) 392 HEMI Manifold Upgrade
The intake manifold of the 6.4L HEMI is equipped with dynamic runners. For engine speeds up to 4,800 rpm, the 392 manifold switches to long-runner mode, which boosts both power and torque. Then, for improved top-end power, it transitions to short-runner mode (typical of 5.7 HEMI manifolds*).
This is a major cause of the 6.4L manifold’s lack of acceleration boosts. At higher RPM, where maximum power is produced, it performs the same function as the original 5.7 manifold. The active runners, however, do work to increase both low and midrange strength.
As before, increases in midrange power of 10–20 whp and 15–30+ wtq have been observed. The 6.4 manifold may be ported for extra more power and torque increases. You may simply replace the 5.7L manifold with the 6.4L V8 HEMI manifold. However, the 5.7 HEMI’s active runners need special wiring and tuning in order to function properly.
This 392 HEMI manifold is a good investment if you want to achieve peak performance with a naturally aspirated engine. Like the 5.7 HEMI intake manifold, this one is made of plastic, so it’s not the best option if looks are your first priority. Adding boost also requires a stronger aluminum manifold.
Updated 5.7 Eagle engines in Ram 1500s employ an intake manifold with active runners similar to those seen in the 6.4 HEMI engines.
2) 5.7L V8 Intake Manifold Porting
The original equipment manufacturer 5.7 HEMI intake manifold can be ported for an additional performance boost. To expand the runner ports, it is enough to just remove some material. The surfaces are then polished to eliminate any potential for turbulent airflow.
It’s a straightforward solution that’s less expensive than going with a 6.4 HEMI engine or custom manifolds. Although the power increases won’t be as spectacular. While you may observe an increase of 5-10whp at the high end, the torque at lower RPMs may suffer slightly.
This isn’t the most efficient or effective update, but it will save you some money. It’s not the best choice if you want to completely overhaul your budget, but it could work if you just need a little bit of a boost.
The intake manifold for the 6.1L HEMI is made of aluminum, and some 5.7 HEMI owners choose to make the switch. In the other hand, we won’t be including that manifold on our recommended list. The standard 345 HEMI manifold can be ported, the 392 HEMI intake can be upgraded, or an aftermarket design can be used.
3) Edelbrock 5.7 HEMI Intake Manifold
We’ll be using a genuine aftermarket 5.7 HEMI intake from here on out. There’s a solid reason Edelbrock is so often used. It’s likewise constructed from aluminum, and it has a design that’s identical to the factory manifold for a 6.1L HEMI engine. The runner taper is 14 inches and the plenum is broader. To further lessen port restriction, Edelbrock shifted the injector bosses.
Briefly said, the Edelbrock 5.7 HEMI intake manifold is preferable to the 6.1L manifold if you’re looking to upgrade your engine’s performance. This manifold costs around $1,080, which is comparable to the cost of installing a 6.1 HEMI engine. Approximately 5 to 15 additional top-end horsepower can be anticipated. You’ll get more peak power, but at the expense of some of the engine’s midrange torque.
4) Gen 3 HEMI Holley Sniper Intake Manifold
Holley Performance’s Sniper Intake Manifold comes in last. Just like the other items on this list, it is designed to work with the 5.7L Gen III HEMI used in vehicles manufactured after 2009. The high-flow fuel-raid kit comes with mounting hardware and o-rings.
Intake manifolds can be expensive, but this one is one of the more affordable options on our list at $675. It is expected that this manifold will provide similar increases of 5-15whp with only a slight reduction in low-end acceleration.
However, the 5.7 HEMI Holley Sniper intake manifold is a thing of beauty. This manifold is a great buy if you need a long-lasting component with a sleek design. For top-tier efficiency, the 392 HEMI manifold with working runners is still your best bet.
See how great the Holley manifold really is in the attached video (with a short sound clip following the install).
Is a 5.7 HEMI Manifold Upgrade Worth It?
I’d say yes and no. This is another example of a subjective issue. Just what do you plan to do with the vehicle? Is an intake manifold a worthwhile investment for you at this time? Does your build make better use of different mods? There is no magic bullet solution.
As a last point, an intake manifold can be a fantastic upgrade for the 345 HEMI. As a result, we don’t believe the 5.7 V8 is a necessary expenditure. But that’s just us expressing our personal viewpoint. It could be a great upgrade if you despise the plastic manifold’s design and want a more durable and aesthetically pleasing aluminum intake.
Intake modifications are recommended for a NA 5.7 HEMI that wants to perform at its best. Just below tuning, headers, and cams, we would put this upgrade. Dodge 5.7 HEMIs can benefit significantly from the installation of a high-quality intake manifold.
I was wondering if anyone have any feedback on 345 Mopar intakes. Would you look into getting one?
