Long Block vs Short Block: What You're Actually Buying

A long block includes the engine block, cylinder head, crankshaft, pistons, and valvetrain. A short block contains only the block, crankshaft, and pistons. The main difference is that a long block gives you more of the engine assembly, so you need fewer parts from your old engine.

When you're shopping for a replacement engine, you'll hear these two terms thrown around. It's easy to get confused. Both are partial engine assemblies, but they're built differently. The choice between them affects what you'll spend and how much work you'll need to do.

What Is a Short Block?

A short block is a bare-bones engine assembly. It includes the engine block as the foundation. Inside, you'll find the crankshaft and pistons. That's really it.

Everything else is missing. The cylinder heads are not included. The valvetrain parts are absent. Intake and exhaust manifolds are not there. Alternators, power steering pumps, and other accessories are definitely not included.

You'll need to reuse these parts from your old engine. That means pulling off your old cylinder heads. You'll transfer your valves, rocker arms, and pushrods or cam followers over to the new short block. You remove your intake manifold, exhaust manifold, alternator, and water pump. Then you bolt everything onto the short block.

This is labor-intensive. You're doing a lot of disassembly and reassembly work. If your old engine parts are in good shape, you can save money up front. The short block costs less than a long block. But your total project cost climbs when you add labor.

Short blocks work best for:

• People who already have good used parts to transfer
• DIY builders with mechanical skills
• Budgets that are tight on money
• Engines where the accessories are still reliable

What Is a Long Block?

A long block is a more complete engine assembly. It has everything a short block has, plus much more.

A long block includes the engine block, crankshaft, and pistons just like a short block. But it also includes the cylinder head. That head comes with valves, springs, keepers, and rocker arms installed. The valvetrain is complete and ready to go.

Some long blocks include intake and exhaust manifolds. Others have gaskets and seals already in place. You don't have to transfer these from your old engine.

What a long block does not include are external accessories. The alternator doesn't come with it. Neither does the power steering pump, water pump, or air conditioning compressor. You'll reuse your old accessories.

Long blocks come ready to bolt into an engine bay with minimal preparation. You transfer over your accessories and bolt everything together. The installation is straightforward. You're not doing major disassembly work on the core engine.

Long blocks work best for: First-time engine swappers

• People who want the job done faster
• Those who want minimal risk of problems
• Anyone whose old accessories are still good

Long Block vs Short Block: Side by Side

Here's what each assembly includes:

Which One Should You Buy?

The right choice depends on three things. First, check your skill level and time available. Second, look at your budget. Third, assess your old engine parts.

Choose a short block if:

You have mechanical skills and time to spare. You're comfortable taking apart an engine and transferring parts. Your old cylinder heads are in good condition. Your alternator, water pump, and accessories work fine. You want the lowest upfront cost.

Choose a long block if:

This is your first engine swap. You want the job done in a weekend. You want less room for error. Your old cylinder head is cracked, warped, or worn out. You'd rather pay more up front than deal with problems later.

The truth is, most people choose a long block. The speed and reliability are worth the extra money. You avoid headaches. You don't discover problems mid-swap when it's too late to turn back.

How DMV Engines Ship Your Long Block

At DMV, we ship long blocks that are ready to install. Your new long block arrives with the cylinder head bolted on. The valvetrain is assembled. Gaskets and seals are in place.

You transfer your old accessories onto the long block. Your alternator goes on. Your power steering pump goes on. Your water pump bolts on. Your intake manifold might be reused depending on your engine.

Then you bolt the whole assembly into your engine bay. You reconnect your hoses and wiring. You fill it with coolant and oil. You fire it up.

This is why we ship long blocks. You get a complete engine package without the work of transferring cylinder heads. You're back on the road faster.

Browse Our JDM Engines Collection

We have long block engines for most models. Browse our JDM Engines collection to find the right fit for your vehicle. We stock everything from Honda and Toyota engines to Nissan and Mazda powerplants.

Learn About the RAV4 2AZFE Long Block.

Want to see a real example of what's included? Check out our RAV4 2AZFE long block engine to see exactly what you get and what parts you'll transfer from your old engine.

Understanding Crate Engines

You might hear the term "crate engine" during your research. A crate engine is different from both short blocks and long blocks. Want to learn more? Check out our guide on What Is a Crate Engine to understand how crate engines compare.

Engine Assembly Definitions and Standards

For accurate definitions of engine assemblies, we reference industry standards from automotive engineering resources and engine builder guidelines used across the repair and replacement industry.

Shop Long Block Engines Today

Ready to upgrade your engine? Our long block engines come with warranties and quality inspections. Browse our long block engine inventory and find your perfect match.

FAQs

Is a long block a complete engine?

A long block is mostly complete. It has the block, head, crankshaft, pistons, and valvetrain. It's missing external accessories like the alternator and water pump. You reuse those parts from your old engine. So it's not totally complete, but it's complete enough to drop in and run.

Do I need to transfer my intake and sensors?

Most long blocks include the intake manifold. Check your product page to confirm. Oxygen sensors, fuel injectors, and intake air sensors come from your old engine. Bolt them onto the new manifold, and you're done.

Can I use a short block if I'm not a mechanic?

You can, but we don't recommend it. Short blocks require serious mechanical work. You'll be pulling cylinder heads, valves, and valve springs off your old engine. You'll be transferring rocker arms and pushrods. One mistake ruins expensive parts. Long blocks are safer for first-timers.

How long does a long block installation take?

Most shops bolt in a long block in one day. Some jobs take two days if they run into rust or stuck bolts. A short block swap takes two or three days because you're transferring so many parts.

What's the real difference between a long block and a short block?

The long block saves you work. You don't disassemble your old cylinder head. You don't transfer valves and springs. You bolt the new long block in and transfer just the accessories. That's it.

Should I buy used or rebuilt?

Used long blocks are cheaper and often run just as strong. Rebuilt engines are refreshed and carry better warranties. Both are good choices. Used engines are better for tight budgets. Rebuilt engines are better if you want peace of mind.

Can a long block increase my horsepower?

A long block is a direct replacement. It won't add power to your old engine. If you want more horsepower, you need a different engine entirely, not just a swap with the same model.