LS 862 Heads: Are They Any Good?

Hey guys, let's dive into the world of LS engines and specifically, the LS 862 heads. If you're tinkering with an LS swap or just trying to understand the nitty-gritty of your engine, you've probably heard about these cylinder heads. So, the big question is, are they any good? The short answer is: it depends. The 862 heads, also known as the LS truck heads, are a popular choice for budget builds, and understanding their strengths and weaknesses is super important. We'll break down the specs, performance potential, and ideal applications of the 862 heads to help you decide if they're the right fit for your project. This is going to be fun! Let's get started.

Understanding the Basics: What are 862 Heads?

Alright, first things first. The 862 cylinder heads are factory-installed heads that were commonly found on various LS-based truck engines, such as the 4.8L and 5.3L engines. They're part of the “cathedral port” family, which means they have the classic rectangular intake ports that have become a trademark of LS engines. They were designed for durability and efficiency, aimed at providing good torque and drivability in the trucks they came in. However, that doesn't mean they can't be used for performance applications, too! The 862 heads are typically made from cast aluminum, offering a good balance of strength and weight. The key to understanding their potential lies in their design features, which we'll get into shortly. They are a cost-effective option for those looking to upgrade their engine without breaking the bank. So, before you start throwing money at your engine, you should learn about these heads.

Let's get into the main characteristics. The 862 heads are pretty common. They were used extensively in the 4.8L and 5.3L engines that General Motors produced for trucks and SUVs from 1999 to 2007. They're recognized by the casting number 862, usually found on the underside of the cylinder head. These heads have a 61cc combustion chamber volume, which helps to maintain a good compression ratio, especially in the engines they were originally designed for. The intake ports are moderately sized, typically flowing around 200-210 CFM (cubic feet per minute), which is fine for the intended truck applications. But we need to remember that these were truck engines. The exhaust ports are a bit smaller, which can be a limitation for high-performance builds, but still work great for stock engines. Their valve sizes are also smaller, typically 1.89-inch intake and 1.55-inch exhaust valves. Understanding these specs will help us understand their capabilities. This will help you to know if the 862 heads suit your needs.

862 Heads Specs and Performance Potential

Okay, now let's talk about the important stuff: specs and performance potential. When considering the 862 heads, it's crucial to understand their design and how it impacts their performance. Starting with the intake ports. They are relatively small compared to other LS heads. This can limit airflow, especially at higher RPMs. If you're building a high-horsepower engine, the intake ports might become a bottleneck. The exhaust ports are also a bit restricted, impacting the engine's ability to get rid of burnt gases quickly. This, again, limits high-end power potential. But don't let these facts discourage you! They can still be quite effective for moderate performance applications. The combustion chamber volume is about 61cc, which, combined with the right pistons, can help achieve a good compression ratio. This is essential for power and efficiency. Valve sizes are moderate, with 1.89-inch intake valves and 1.55-inch exhaust valves. Larger valves can improve airflow, but the stock sizes work well for many applications. They're good for daily driving or towing. The 862 heads are not the best choice if you're looking to build a high-horsepower, track-only engine. There are better options out there. However, if you are working with a budget, these heads can provide a significant boost in performance compared to the original heads, especially when paired with a good cam and other supporting mods. The potential is there, but you have to be smart about it.

Now, let's get into performance numbers. Out of the box, the 862 heads can flow around 200-210 CFM on the intake side. This is sufficient for a stock engine, but as we said, they may limit the potential of more aggressive builds. With some basic porting and polishing, you can increase airflow significantly, up to 240 CFM or even more, depending on the work. This is when the 862 heads start to shine! With some upgrades, they can support power levels of 400-450 horsepower in a well-built engine. Of course, all these numbers depend on the supporting components, such as the camshaft, intake manifold, and exhaust system. If you are working on a budget, this is a great start. Upgrading the valve springs is a good idea to handle higher RPMs and more aggressive camshafts. Upgrading the valve springs and retainers is also smart. This is especially true if you are planning on installing a performance camshaft.

Pros and Cons of Using 862 Heads

Alright, let's break down the pros and cons to help you make a good decision. First, the pros. The biggest advantage of the 862 heads is their affordability. You can find them at a low price. They're readily available since they were installed in a huge number of LS-based trucks and SUVs. This makes them a perfect choice for budget builds. The availability also makes them super easy to find. As mentioned above, the 862 heads are pretty reliable and durable, which is what the trucks needed. They're great for daily driving and towing applications. They can also work great for mild performance upgrades when paired with the right components. They're a good choice for those who want a modest power increase without breaking the bank. The last advantage of the 862 heads is that they are easy to modify. Porting, polishing, and valve upgrades are available, which can increase their performance potential, making them a great base for customization. Keep this in mind when you are considering the 862 heads.

Now, let's go over the cons. The stock airflow is somewhat limited. This may restrict the high-end power of the engine. The small intake and exhaust ports can be a bottleneck in high-performance applications, as we mentioned earlier. This means you will not be able to achieve the maximum performance from your engine. The valves, particularly the exhaust valves, are small. While fine for stock applications, they may not be ideal for aggressive performance builds. You can always change the valves. Another con is that the 862 heads may not be the best choice for all-out racing applications where maximum horsepower is the goal. There are better heads available. They're not going to be competitive with higher-end, aftermarket heads in terms of raw power output. You will have to do some modifications for better performance. They need porting and polishing to really shine. They need upgraded valve springs and other components to handle more aggressive camshafts and higher RPMs. Now you can make a good decision.

Ideal Applications for the 862 Heads

So, where do the 862 heads shine? What are the ideal applications for these heads? They are great for budget builds. If you're looking to build a budget-friendly LS engine, the 862 heads are a great option. They are cost-effective, readily available, and can provide a noticeable performance boost over stock heads, especially when paired with a more aggressive camshaft. They are also suitable for mild performance upgrades, such as streetcars and daily drivers. The 862 heads can provide a good balance of power and reliability for those who want a noticeable performance boost without sacrificing drivability or reliability. They are very reliable. They are an awesome option for truck engines. If you're working on a truck engine, the 862 heads are a perfect match. They were originally designed for truck engines. They work great for towing and hauling. Another good application for the 862 heads is hot rods and project cars. They are a good choice for project cars, offering a cost-effective way to get an LS engine running and provide some performance upgrades. They are also great for a first LS swap. If you're new to the LS world, the 862 heads are a great place to start. They're simple and easy to work with.

Modifications and Upgrades for 862 Heads

Alright, let's talk about how to get even more out of these heads! Modifications and upgrades can significantly improve the performance of the 862 heads. One of the most common upgrades is porting and polishing. This process involves smoothing and enlarging the intake and exhaust ports to improve airflow. Even a basic port job can increase airflow significantly, allowing the engine to breathe better and produce more power. You can also upgrade the valve springs. When installing a more aggressive camshaft, or if you plan to rev your engine higher, upgrading the valve springs is a must. High-quality valve springs will help prevent valve float and ensure the valves open and close properly at higher RPMs. You can also upgrade the valves. While the stock valves are adequate for many applications, upgrading to larger valves can further improve airflow and increase power, especially on the intake side. This is often done when porting the heads to maximize the benefits. Another important upgrade is the camshaft. A well-chosen camshaft can unlock the potential of the 862 heads, especially when combined with porting and valve upgrades. Consider the desired power band and intended use of your engine. Always check the valve-to-piston clearance when upgrading the camshaft. This is a critical step to ensure that the valves do not hit the pistons during operation. It's smart to upgrade the valve retainers. Upgrading the valve retainers is a good idea to handle the higher spring pressures and RPMs associated with performance upgrades. This will increase the reliability of the engine. Finally, you can upgrade the intake manifold. Pairing the 862 heads with a more efficient intake manifold can improve airflow and performance. Choose an intake manifold that matches your engine's intended use and the camshaft you're using. These upgrades can greatly increase the engine's performance.

Conclusion: Are 862 Heads Right for You?

So, are 862 heads any good? In short, yes, but it depends on your goals and budget. They're excellent for budget builds, offering a great balance of performance and affordability. They are perfect for daily drivers. However, they might not be the best choice for all-out racing applications or for those seeking maximum horsepower. The LS 862 heads are a cost-effective option for anyone looking to upgrade the performance of their LS-based engine. They offer a good balance of performance and reliability, especially when combined with the right upgrades. They're perfect if you're looking for a simple upgrade. They're also an amazing choice if you want to get your engine working fast. Evaluate your needs and expectations, consider your budget, and choose the cylinder heads that best suit your project. They're great for various projects. By understanding the specifications, potential, and ideal applications of the 862 heads, you can decide if they are the right choice for your LS engine build. Happy wrenching, and enjoy the LS world!"