What is a Subaru Longblock? A Complete Guide

Before you buy a single part, you need a clear vision for your Subaru. Are you building a high-revving track machine, a responsive daily driver, or a torque-focused overlanding rig? The answer dictates every decision you’ll make, especially when it comes to the engine. A performance Subaru longblock is a strategic investment that directly aligns your engine’s capabilities with your ultimate goal. The internal components and cylinder head configuration in a longblock built for a track-prepped STI are fundamentally different from one designed for a Forester. Choosing the right one ensures your car not only makes power but delivers it in a way that suits your driving style perfectly.

Key Takeaways

• Start with a Strong, Pre-Assembled Core: A longblock gives you a major head start on an engine build by providing a professionally assembled short block, cylinder heads, and valvetrain. This saves complex labor and ensures critical components are set to precise specifications, creating a reliable foundation for power.
• Select an Engine That Fits Your Goals, Not Just Your Car: The right longblock is about more than model compatibility. Define your performance targets and driving style first—whether for daily driving, track use, or overlanding—and choose an engine with internals specifically designed to meet those demands.
• Plan Beyond the Engine Itself: Your investment doesn't end with the longblock. A professional tune is essential to safely optimize performance, so budget for it from the start. Prioritize builders who offer a clear warranty, as it reflects their commitment to quality and protects your project long-term.

What is a Subaru Longblock?

If you're looking to get more power out of your Subaru, you've probably heard the term "longblock" thrown around. Think of a Subaru longblock as a partially assembled engine—a major step up from a bare short block. It's the heart of your vehicle, containing the core components that create power, all pre-assembled to save you time and complexity. For enthusiasts planning a significant engine upgrade or replacing a tired motor, a performance longblock provides a robust foundation built with stronger components than what came from the factory. This makes it an ideal starting point for builds aiming for higher horsepower, whether you're hitting the track or building a capable overlander. It strikes a balance between a complete, drop-in engine and a ground-up custom build, offering a practical path to serious performance gains.

Longblock vs. Short Block vs. Complete Engine

When you're shopping for engine components, it's crucial to know the difference between your options. A short block is the most basic assembly, typically including the engine block, crankshaft, and connecting rods. It’s the foundational piece, but you'll need to add cylinder heads and many other parts to make it run. A longblock, on the other hand, comes with the short block components plus the cylinder heads, camshafts, and valvetrain already installed. This saves significant assembly time. Finally, a complete engine is essentially a turn-key solution, arriving fully assembled with everything from the fuel system to the turbo, ready to be dropped into your car.

Key Components in a Subaru Longblock

A Subaru longblock is much more than just a block with a few parts. It’s a carefully assembled package that includes the most critical internal engine components. Inside a typical performance longblock, you'll find the cylinder block, a complete and loaded cylinder head, crankshaft, camshafts, pistons, rings, and connecting rods. These are the moving parts that do the heavy lifting. Because these core components come pre-assembled, you can be confident that critical tolerances and specifications are set correctly. This makes it a reliable base for all your other performance parts, ensuring everything works together seamlessly.

How a Longblock Improves Performance Over Stock

A stock engine is designed for daily driving, but a performance longblock is built for power. The real advantage comes from the upgraded internal components, which are often forged or billet materials designed to handle higher stress, heat, and horsepower. This stronger foundation allows you to safely run more boost and support other modifications, like a larger turbo. Installing a performance longblock fundamentally changes your engine's airflow and capabilities, which is why a professional engine tuning service is essential to dial everything in. A proper tune ensures your new engine runs efficiently and reliably while maximizing its power potential far beyond what a stock motor could ever handle.

The Pros and Cons of a Subaru Longblock

Choosing a longblock for your Subaru is a major decision, and it comes with its own set of trade-offs. While it offers a fantastic foundation for serious power, it’s important to weigh the benefits against the potential drawbacks to make sure it’s the right move for your build. Understanding both sides will help you invest your money wisely and set clear expectations for your project.

The Upside: Cost, Installation, and Power Potential

One of the biggest draws of a longblock is that it hits a sweet spot between convenience and cost. Because it arrives as a complete short block with professionally assembled cylinder heads, camshafts, and valvetrain, it saves you a ton of installation time and complexity. This pre-assembly often makes it a more affordable route than a complete crate engine, both in terms of parts and labor. For enthusiasts looking to build a high-performance engine for their Subaru WRX, a longblock provides a robust core that’s ready to handle significant power upgrades right out of the box.

The Downside: Warranty Limitations and Compatibility

While a longblock simplifies much of the engine build, it’s not a complete drop-in solution. You’ll still need to transfer several key components from your old engine, like the intake and exhaust manifolds, turbocharger, fuel system, and other accessories. This means you have to be sure your existing parts are in excellent working condition. Another critical point is the warranty. Most longblock warranties cover the core internal components but typically won’t cover the external parts you move over. If an injector or oil pump fails and causes damage, it might not be covered, so it's crucial to read the fine print.

Debunking Common Myths About Longblock Reliability

A few persistent myths about built engines float around the Subaru community. A common one is that high power-handling capability automatically equals reliability. The truth is, reliability comes from a balanced combination of quality components, precision assembly, and expert engine tuning services. Simply using parts rated for 1,000 horsepower doesn't guarantee a bulletproof engine if the tune is off. Another misconception is that every high-power EJ-series engine needs to be sleeved. While sleeving has its place in extreme builds, modern solutions like our Subaru Engine Power Blocks can significantly strengthen the stock block for a fraction of the cost, providing the durability needed for most high-performance applications.

What to Look For in a Subaru Longblock

Choosing a longblock is one of the biggest decisions you’ll make for your Subaru build. It’s the foundation for all the power and reliability you’re aiming for. But with so many options on the market, it’s easy to get overwhelmed. To make the right choice, you need to look past the price tag and focus on the specifics of the build, its compatibility with your car, and how it aligns with your performance goals. Let’s break down the key factors to consider so you can invest in an engine that delivers on its promises.

EJ vs. FA Series: Which Engine is Right for You?

The first step is identifying the right engine series for your vehicle. Subaru’s two most prominent performance engine families are the EJ and the FA. The EJ series, including the classic EJ25, powered the WRX and STI for decades and has a massive aftermarket following. It’s known for its raw, analog feel and is a proven platform for high-horsepower builds. The newer FA series, like the FA20 and FA24, is found in the latest WRX and BRZ models. These engines feature modern technology like direct injection, offering a different power curve and unique tuning potential. While your car’s original engine will usually dictate your choice, it’s crucial to select a longblock built specifically for your series to ensure a seamless fit and optimal performance.

Power Ratings: Turbo vs. Naturally Aspirated

Not all longblocks are created equal. They are specifically engineered to handle different levels of stress and power. A longblock intended for a naturally aspirated Subaru BRZ will have different internal components than one built to withstand 30 pounds of boost in a track-prepped STI. Before you buy, be clear about your power goals. Are you aiming for a reliable 350-horsepower daily driver or a 600-horsepower weekend warrior? Reputable builders design their engines for specific power targets, using forged pistons, stronger connecting rods, and other durable performance parts to ensure long-lasting reliability. Always check the longblock’s horsepower rating and make sure it provides a safe margin above your ultimate goal.

Engine Compatibility for Your WRX, STI, or BRZ

Subaru has made countless small changes to its engines over the years. A longblock for a 2006 WRX won't be a simple drop-in for a 2016 model due to differences in sensors, wiring, and cylinder heads. Compatibility is about more than just the engine code; it’s about the specific model and year of your car. Whether you drive a WRX, STI, Forester, or Crosstrek, you must verify that the longblock is a direct match. This ensures that all connections, from the intake manifold to the exhaust ports, line up perfectly, saving you from major headaches during installation. When in doubt, always consult with the engine builder to confirm fitment for your specific Subaru WRX upgrades.

Key Factors for Performance and Durability

A longblock is more than just a collection of parts; it’s a complete system that includes the assembled short block plus the cylinder heads. The quality of these components and the precision of the assembly process are what separate a reliable engine from a ticking time bomb. Look for builds that use high-quality forged internals from trusted brands. Pay attention to the details of the cylinder head work, including the valves, springs, and camshafts, as this is where much of the engine’s character and power potential comes from. A quality longblock is assembled in a clean environment to precise tolerances. This meticulous process ensures everything works together perfectly, giving you a durable engine that’s ready for a professional tune. Proper engine tuning services are the final step to realizing your new longblock’s potential safely.

Where to Find and Price Your Subaru Longblock

Once you’ve decided a longblock is the right path for your build, the next step is finding a reputable source. The market is filled with options, from mass-produced rebuilds to custom-built performance engines. Price and quality can vary significantly, so it’s crucial to do your homework. A quality longblock is a serious investment in your Subaru's performance and longevity, and knowing what to look for will help you make a choice you can be confident in for years to come.

Understanding What Influences Cost

The price of a Subaru longblock is determined by more than just the sum of its parts. A long block is a more complete version of a short block, containing additional components like cylinder heads, camshafts, and valvetrain. This inherent completeness is a major factor in its cost. Beyond that, the price reflects the quality of the internal components—forged pistons and stronger connecting rods cost more than OEM-spec parts—as well as the builder's expertise and labor. A hand-built engine from a shop with a long history in performance tuning will carry a different price tag than a standard remanufactured unit.

Crawford Performance: Our Longblocks and Warranty

At Crawford Performance, we build custom long block engines for Subaru WRX, STI, and BRZ models designed for high power, strong performance, and lasting reliability. We don’t believe in one-size-fits-all solutions. Each engine is assembled to meet the specific demands of your build, whether you're aiming for a responsive daily driver or a track-ready monster. We stand behind our craftsmanship, which is why all Crawford Long Blocks come with a 12-month or 12,000-mile warranty. This gives you peace of mind knowing your investment is protected by a team with decades of Subaru performance experience.

How to Compare Different Suppliers

When shopping for a longblock, you’ll come across various suppliers, each with different offerings. For example, some companies sell a wide range of Subaru long block engines for models like the WRX, STI, Outback, and Forester. You'll find options for both turbo and non-turbo applications, with different engine types like DOHC and SOHC. When comparing, look beyond the final price. Scrutinize the build sheet to see exactly which components are included. Does one builder use superior bearings or stronger head studs? Does the supplier offer a warranty? Answering these questions will help you compare apples to apples and find the best value for your performance goals.

Signs of a Quality Build and Customization Options

A top-tier longblock is more than just a collection of parts; it’s a precision-engineered system. One of the biggest signs of a quality builder is the ability to offer customization. High-performance engines are often built to order, meaning they can be tailored to your specific needs, from power goals to driving style. Look for a builder with a proven track record. For instance, Crawford Performance has been a trusted name in Subaru racing for over 20 years, a history that informs every engine we build. A quality supplier will be transparent about the performance parts they use and confident enough in their work to offer a solid warranty.

Choosing the Right Longblock for Your Build

Selecting a longblock is one of the most significant decisions you'll make for your Subaru. It’s the heart of your build and a major investment, so it’s crucial to get it right. The perfect longblock isn't just about the highest horsepower rating; it's about finding the ideal match for your specific goals, budget, and driving style. A well-chosen engine will deliver reliable power and transform your driving experience, whether you're aiming for a responsive daily driver or a dedicated track machine.

To make the best choice, you need to look beyond the spec sheet. Consider how the engine will integrate with your existing and future modifications, who will handle the installation and tuning, and what level of long-term reliability you expect. Thinking through these key areas will help you build a car that’s not only powerful but also dependable and enjoyable to drive for years to come.

Match the Engine to Your Performance Goals

The first step in choosing a longblock is to define what you want to achieve. Are you building a reliable daily driver with a bit more punch, a weekend warrior for the track, or a rugged overlanding rig built for endurance? Your answer will guide your decision. A longblock is a non-running engine that includes the short block plus key components like the cylinder heads, which are critical for airflow and power production. The specific combination of these parts should directly support your end goal.

For instance, a build focused on daily driving might prioritize a smooth powerband and long-term reliability over peak horsepower. A track-focused build for a Subaru STI will require components designed to handle high RPMs and extreme heat. An overlanding build for a Crosstrek or Forester needs to deliver consistent torque and withstand harsh conditions. Be honest about how you’ll use your car 90% of the time, and choose a longblock built for that purpose.

Plan for Installation and Professional Tuning

Installing a performance longblock is not a simple plug-and-play operation. It fundamentally changes your engine's characteristics, and dropping it in without a proper tune is a recipe for disaster. A professional tune is non-negotiable. The new components, from pistons to cylinder heads, alter airflow and combustion dynamics, and your vehicle’s ECU must be recalibrated to account for these changes. A skilled tuner will optimize fuel and ignition timing to not only extract maximum power safely but also ensure your new engine runs smoothly and reliably.

Factor the cost of professional installation and a dyno tune into your total budget from the very beginning. This is not the place to cut corners. Working with a shop that has extensive experience with Subarus will save you from potential headaches and costly failures down the road. Proper engine tuning services are just as important as the quality of the longblock itself.

Understand Power Handling and Its Limits

It’s easy to get caught up in high horsepower numbers, but there’s a common misconception that power handling equals reliability. A longblock rated for 800 horsepower is built with components strong enough to withstand that level of stress, but it doesn't mean it will be reliable if you run it at that limit every day. Think of power ratings as the engine's maximum potential, not its recommended daily output. Pushing any engine to its absolute limit will shorten its lifespan.

True reliability comes from a balanced setup where all components work in harmony. A high-horsepower longblock requires a robust supporting cast, including an upgraded fuel system, a larger turbo, an efficient cooling system, and a drivetrain that can handle the extra torque. For most drivers, a well-balanced build with a realistic power goal—like a responsive 400-horsepower Subaru WRX—is far more enjoyable and sustainable than a temperamental 700-horsepower monster that’s constantly in the shop.

Consider the Warranty and Long-Term Reliability

When you invest in a performance longblock, you’re not just buying parts; you’re buying peace of mind. A comprehensive warranty is a builder’s vote of confidence in their product, materials, and assembly process. It’s a crucial factor that reflects the quality and expected reliability of the engine. Before you buy, read the fine print. Understand what the warranty covers, its duration, and any conditions that must be met, such as requiring professional installation or a specific break-in procedure.

A reputable builder will stand behind their work. For example, at Crawford Performance, we back our longblocks with a 12-month/12,000-mile warranty, setting a standard for quality and customer assurance. Choosing a pre-assembled longblock from an experienced builder not only saves you the time and complexity of sourcing individual performance parts but also provides a single point of contact and a clear warranty if any issues arise.

Related Articles

• The Ultimate Subaru Short Block Buyer's Guide
• High-Performance Subaru Short Blocks: A Buyer's Guide
• High-Performance Subaru Short Blocks & Long Blocks Engine

Frequently Asked Questions

Why should I choose a longblock instead of just building up from a short block? Opting for a longblock is a strategic move that balances cost, convenience, and quality control. While building from a short block gives you total control, it also requires specialized tools and expertise to correctly install and set the tolerances for the cylinder heads, camshafts, and valvetrain. A longblock arrives with all those critical components professionally assembled, which saves significant labor time and reduces the risk of assembly errors that could damage your new engine.

What other parts will I need to complete my longblock installation? A longblock is a non-running engine, so you will need to transfer several components from your old motor or purchase new ones. This typically includes your intake and exhaust manifolds, turbocharger, fuel injectors, ignition coils, and all the engine accessories like the alternator and power steering pump. It's a great time to inspect these parts and replace any that are worn to ensure the health of your new engine.

Is a longblock with a high horsepower rating guaranteed to be reliable for daily driving? Not necessarily. An engine's horsepower rating indicates the maximum stress its internal components are designed to handle, not its ideal operating output. True daily-driving reliability comes from a balanced build and a conservative tune. Running an engine at its absolute limit constantly will shorten its lifespan, regardless of how strong the parts are. For a dependable daily driver, it's best to choose a longblock rated well above your power goals.

What happens if I install a performance longblock but skip the professional tune? Installing a performance longblock without a proper tune is one of the fastest ways to destroy your investment. The new components fundamentally change how your engine breathes and processes fuel. Your car's factory ECU settings are not calibrated for these changes and will likely cause the engine to run dangerously lean or rich, leading to catastrophic failure. A professional tune is essential to recalibrate the system, optimize performance, and ensure the engine operates safely.

How do I know if I need an EJ or FA series longblock? The correct engine series for your build is determined by the original engine that came in your Subaru. The EJ series engines, like the EJ25, were used in models like the WRX and STI for many years. The newer FA series engines are found in the latest WRX and BRZ models. To ensure all your existing components and wiring harnesses connect correctly, you must select a longblock that matches your car's specific year and model.