What is a long block engine? Advantages and disadvantages

What is a long block engine? When it comes to building or rebuilding a vehicle, a few decisions are as critical as your choice of engine for powering your new vehicle. For crate engine installations, you’ll often hear the terms short block and long block being thrown around.

If you’re new to the motor assembly game, you’re probably wondering which is better: short block vs. long block? In this case, short and long refers to the completeness of the engine that goes into your car.

What is a long block engine?

A long block engine is, in a sense, a complete version of a short block. In addition to the assembled block, it features a camshaft, lifters, valve-train, and cylinder head. A long block may also come with an oil pan, water pump, and valve covers. Long blocks are usually used when diagnostics indicate that a vehicle needs an engine overhaul.

What is a long block engine

Despite having more components than a short block, a long block engine is not a complete engine package. A long block does not include, among other parts, the fuel system, intake manifold, exhaust manifolds, or electrical components. If you need to replace these components or every other part of the engine assembly, consider ordering a “turn-key” engine.

Some people confuse short block and long block engines with small block and big block engines or refer to them interchangeably. There are significant differences between these terms, starting with the classification of small block or big block engines is a description of engine size. Short block or long block refers to the number of assembly parts included.

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What is a short block engine?

A short block engine is the bottom end of a vehicle’s engine. It includes the cylinder block and a few other critical parts of the engine, such as the crankshaft, cam pistons, and connecting rods. These pieces are also known as the rotating assembly.

Because there are usually slight variations in engine builder companies’ packages, some short blocks may come with camshafts and timing belts. All short block engines require additional parts such as gaskets, cylinder heads, and oil pumps which have to be purchased separately.

Short block engines are ideal for individuals who desire to learn the engine building process on their own. Building a short block engine is a great learning experience and provides a more involved and hands-on approach to engine replacement.

Which engine should I choose?

Generally, a long block engine offers better and more reliable performance than a short block engine. Since long blocks come with more parts preinstalled, they are less likely to malfunction due to faults in the fitting process. Additionally, the components included with a long block wear out evenly and minimize replacement costs.

As with other sub-assembled auto parts, not all long blocks will work well with the make and model of your vehicle. To match the performance of the stock engine, you have to ensure the long block that you are installing is compatible with the electronic control unit and the transmission system of your car.

On the other hand, a short block engine gives you more choice over the range of external parts you can install. You can expect a short block to perform better than a long block if you invest in quality parts and accessories. Consider, for example, cylinder head assembly, which directly affects the engine’s horsepower output.

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What is a long block engine

Unlike a long block, a short block does not come with a preinstalled cylinder head. It gives you the freedom to choose whichever head fits the performance you would like. A great head on a great short block can produce more power than a stock engine.

Consider going for a short block over a remanufactured engine if the significant internal parts of the old unit have been damaged beyond repair, but other external parts are functional. If these pieces are damaged, and the total cost of purchasing the short block and additional components approach the cost of buying a long block, consider getting a long block for your engine swap instead.

Long blocks over complete engines

A complete engine is just like it sounds… “fan to flywheel” drop in ready to go. A complete engine includes all of your hard internal parts as well as the fuel system, turbo, pumps, housings and oil pan. A complete engine can be bolted up and attached to the transmission rather quickly and requires no additional labor to work on the engine.


A complete drop-in option built to the exact serial number and arrangement number will be the quickest way to get back on the road. Lead time can be a matter of days vs. 2 weeks or more with a remanufactured longblock. Complete engines usually are dyno tested and come with a complete warranty on the entire unit.


The price of a complete drop-in from the dealer will cost considerably more than a longblock option; sometimes double the price. Complete engines (crate engines) not build to a specific serial number sometimes may not be a 100% exact fit.

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Some customers will look to swap in a different model or higher horsepower unit but not expect the intensive labor costs associated of not doing a like-for-like swap.

Many times complete engine swaps will require different motor mounts, work to upgrade the suspension, axles as well as configuring the ECM of the truck to work with the ECM of the new engine. Compatibility is important when doing engine swaps.


What makes an engine a long block?

Long block engines get their name from the fact that they have a longer list of components. They contain the engine block, crank and pistons, just like the short block, but they also have a cylinder head, camshaft and valve train. In some cases, you’ll also get an oil pan and valve covers with your purchase.

What is better short block or long block?

In addition, the long block has more assembled parts and may include a warranty, providing a peace of mind and less work to complete. If you prefer to customize the engine on your own, then starting with a short block and building it to completion may be the preferred option.

Is a long block a new engine?

A long block does not include the fuel system, electrical, intake, and exhaust components, as well as other components. A long block may include the balancer/damper, timing cover, oil pan and valve covers. A long block engine replacement typically requires swapping out parts from the original engine to the long block.

Above is information about What is a long block engine? that we have compiled. Hopefully, through the above content, you have a more detailed understanding of Long blocks over complete engines Thank you for reading our post.

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