LS Intake Manifold Torque and Sequence

When it comes to standard intake manifolds on, say, four-cylinder engines, hardly anyone pays attention to the correct volt torque. However, the intake manifold torque for LS engines is extremely important to both avoid overtightening them and stripping the cylinder head threads, but also to avoid under-tightening them and causing vacuum leaks. Moreover, LS manifold bolts require two passes plus a specific sequence, but more on that later.

The LS intake manifold torque is 44 in-lb for the first pass and 89 in-lb for the second and final pass. Also, there is a specific sequence or order in which you need to tighten the bolts.

LS Intake Manifold Torque Explained

Tightening the LS intake manifold exactly as the manufacturer recommends is crucial to avoid damage and possible engine running issues later. As we already mentioned, if you under-tighten the bolts, you are risking vacuum leaks that will throw off the car’s air/fuel ratio and result in lower performance, fuel economy, and long-term engine health.

On the other hand, if you overtighten the bolts, you are risking damaging the cylinder head threads, which is a huge issue in and of itself. Furthermore, you need to tighten the intake in two passes with different torque settings, plus in a specific sequence.

The specific sequence ensures that the intake manifold is tightened equally all around to avoid any low or high-pressure spots. In other words, high or low bolt torque. Also, it ensures that all the bolts are stretched out equally and to the correct length so that the clamping force on the manifold is uniform and there are no leaks. 

Now, the two LS intake manifold torque passes have different torque specs. That means you need to tighten all the bolts too, in this case, 44 in-lb in the specific sequence we will go into shortly. After that, in the same sequence, tighten all the bolts to 89 in-lb for the second pass. The second pass is also the final pass which means the manifold is tightened correctly at that point.

Now, for the sequence. All the LS intake manifolds have ten bolts, five on each side of the manifold. You need to start with the middle bolt on the left side (looking from the front of the car), then move to the middle bolt on the right side. After that, tighten the one above the second bolt and then the one below the first bolt (below is closer to the front of the car).

Next, the one above the first bolt, and then, the one below the second bolt. By now, you will notice that after the first two bolts, the sequence becomes a crisscross pattern. But,  to simplify the sequence, we can present it in a different way.

LS Intake Manifold Bolt Sequence

Below, each number represents a bolt on the intake manifold, where number one means it’s the first bolt you need to tighten, followed by two, and so on. Also, you should imagine standing in front of the car and looking down at the intake manifold.

What Is the LS Intake Manifold Torque

The LS intake manifold torque specs on all variations of the engine are the same, although there are some mentions that the LS3 requires a different bolt torque, specifically 108 in-lb. However, that’s not something we can confirm as all official sources and service manuals state the bolt torque and tightening sequence is the one you will find below.

 Still, you will find everything below sorted by generations and engine codes, plus you will find all the models and production years each engine went into. That may help you find parts for your engine but also help you learn more about it.

Third Generation LS Rocker Arm Torque Specs (1999-2007)

The intake manifold torque specs for the third-generation LS engines are pretty simple since only two variations of the engine ever came out, and the specs are the same. So, even though it’s hard to tell the difference between the LS1 and LS6, there is no need for this purpose, but you can still find your car model below to see which LS engine you have.

LS1

Intake Manifold Torque Specs – 44 in-lb > 89 in-lb

Vehicles With the LS1 Engine

LS6

Intake Manifold Torque Specs – 44 in-lb > 89 in-lb

Vehicles With the LS6 Engine

Fourth Generation (2005-2020)

The fourth-generation Chevy small block took the LS series to its full potential. There were the standard LS1 and LS6 replacements, the LS2 and LS3, the front-wheel drive-only LS4, and three record-breaking performance versions, the LS7, LS9, and LSA. The fourth-gen LS intake manifold bolt torque specs are the same for all, but you also need the supercharger cover bolt torque and sequence for the LS9 and LSA, but you can find both further below.

LS2 

Intake Manifold Torque Specs – 44 in-lb > 89 in-lb

Vehicles With the LS2 Engine

LS3

Intake Manifold Torque Specs – 44 in-lb > 89 in-lb

Vehicles With the LS3 Engine

LS4

Intake Manifold Torque Specs – 44 in-lb > 89 in-lb

Vehicles With the LS4 Engine

LS7

Intake Manifold Torque Specs – 44 in-lb > 89 in-lb

Vehicles With the LS7 Engine

LS9

Intake Manifold Torque Specs – 44 in-lb > 89 in-lb

Superchargarger Cover Bolt Torque Specs – 44 in-lb > 89 in-lb

Vehicles With the LS9 Engine

LSA

Intake Manifold Torque Specs – 44 in-lb > 89 in-lb

Supercharger Cover Bolt Torque Specs – 44 in-lb > 89 in-lb

Vehicles With the LSA Engine

LS9 and LSA Supercharger Cover Bolt Tightening Sequence

Here, the same goes for the intake manifold sequence. Each number represents a bolt, the orientation is below and above the numbers, and each number represents the order, starting with number 1 and ending with 17.

FAQs:

Q: How tight should the bolts on an intake manifold be?

As a rule of thumb, you should tighten intake manifold bolts to roughly 100 in-lb. However, if you are going to use a torque wrench, it’s best to find the correct bolt torque specs for your specific vehicle to avoid snapping the bolts or destroying the cylinder head threads.

Q: What is the torque for a Vortec intake manifold?

The bolt torque for a Vortec intake manifold is 61 in-lb for the first pass, 106 in-lb for the second pass, and 12 ft-lb for the third and final pass., but keep in mind that the torque specs may differ between Vortec generations, so its best to find the torque specs for a specific Vortec engine. 

Q: What are the torque specs on an LS engine?

The bolt torque specs on an LS engine depend on the component and the generation or code name of the engine. All LS engines have whole lists of bolt torque specs, one for each component, plus the LS engine has almost a dozen variations. For example, the 5.3 LS intake manifold torque specs may not be the same as the 6.0 LS intake manifold torque specs.

Q: Do I need a torque wrench for the intake manifold?

Technically, yes, you do need a torque wrench for the intake manifold. All manufacturers have specific intake manifold torque specs and tightening sequences. That said, most people tighten the intake manifold by hand and have no problems, but a lot of things can go wrong with that method.

Q: Should I use anti-seize on intake manifold bolts?

No, there is no need to use anti-seize on intake manifold bolts. The intake manifold bolts are not prone to rust and don’t experience extremely high temperatures. Using anti-seize on exhaust manifold bolts, however, is highly recommended.

Final Words

Ultimately, the intake manifold bolt torque for LS engines is the same for all variations and code names, and it’s 44 in-lb for the first pass and 89 in-lb for the second and last pass. However, the tightening sequence, as we described, is equally as important.

Also, to remove or install an intake manifold on supercharged LS engines, the LS9 and LSA, you need the supercharger lid bolt torque and sequence as well. The bolt torque is the same, but the sequence is not as you have seen earlier in this article.