Long Block vs Short Block vs Complete Crate Engine: What’s the Difference?
A short block is the assembled bottom end of an engine: the block, crankshaft, connecting rods and pistons. A long block is a short block with the cylinder heads and valvetrain fitted. A complete (or “dressed”) crate engine adds more components, such as the intake manifold, fuel system, ignition or water pump; the exact included parts vary by package. Which one you need depends on how much of your old engine you can reuse and how much assembly you want to do yourself.
Quick comparison
| Level | What it usually includes | What you still need |
|---|---|---|
| Bare block | The cylinder block casting and main caps | Everything else: rotating assembly, heads, valvetrain, timing, oiling, intake, fuel, ignition |
| Short block | Block, crankshaft, rods, pistons, rings and bearings; often the camshaft and timing set on pushrod V8s | Cylinder heads, valvetrain, timing cover, oil pan, intake, fuel, ignition, accessories |
| Long block | Short block plus cylinder heads, camshaft and valvetrain; often the timing cover, oil pan and valve covers | Intake manifold, carburetor or EFI, ignition, water pump, accessories |
| Dressed / complete | Long block plus intake, fuel system (carburetor or EFI), ignition and often the water pump | Engine-specific items such as the flywheel/flexplate, engine controller for EFI, exhaust and mounts, depending on the package |
Manufacturers use these terms slightly differently, so always check the included and not-included parts in each product’s description before you buy.
What is a short block?
A short block is the bottom end, assembled and ready for heads. It suits builders who are reusing good cylinder heads, or who want to choose their own heads, cam and top end. Because the machining and assembly of the bottom end is done for you, it removes the most precision-critical part of an engine rebuild.
Prefer to start even earlier? A bare block plus a rotating assembly lets you spec every part yourself. See our engine blocks, including Dart SBC and 2JZ blocks and GM and Ford Performance aluminum blocks. When comparing blocks, the main caps matter too: see 2-bolt vs 4-bolt main blocks.
What is a long block?
A long block adds the cylinder heads and valvetrain to the short block, so the engine’s core is complete and sealed. You transfer or buy the intake, fuel system, ignition and accessories. Long blocks are popular when the original engine’s intake, carburetor or EFI and accessories are in good condition, which keeps cost down without the work of building heads and setting up a valvetrain.
Examples include the BluePrint SBC 350 long block (341 HP) in our small block Chevy crate engines and the GM Performance LS3 495 HP long block in LS and LT crate engines.
What is a complete or dressed crate engine?
A dressed crate engine adds the parts needed to run, which vary by package: typically the intake manifold, a carburetor or fuel-injection system, ignition, and often the water pump and balancer. Some packages, often called drop-in ready or turn-key, also include the pulleys and front accessories. This is the fastest route to a running vehicle, with the fewest parts to source and match.
BluePrint sells most engines at several dressing levels, from long block to fully dressed carbureted and EFI kits, so you can compare the same engine at different levels of completeness. Browse all crate engines by engine family.
Which one should you buy?
- Your heads and top end are good: a short block may be enough.
- You are reusing the intake, fuel system and accessories: a long block is usually the best value.
- You want the quickest install with matched parts: choose a dressed or complete engine.
- You are building a custom or high-power engine: start from a bare block and rotating assembly, or a short block.
Whichever level you choose, confirm the oil pan, rear main seal, balance type (internal or external) and accessory layout against your vehicle, and check that the engine is legal for your use where the vehicle is registered.
More reading: what is a blueprinted engine.
Frequently asked questions
Does a long block include the intake manifold?
Usually not. A long block typically ends at the cylinder heads and valvetrain, often with valve covers, timing cover and oil pan. The intake manifold comes with dressed or complete engines.
Does a short block include the camshaft?
On many pushrod V8s the camshaft sits in the block, so some short blocks include it and others do not. On overhead-cam engines the camshafts are in the heads, so they come with a long block. Check the product’s included-parts list.
Does a complete crate engine include the ECU and wiring?
Not every package includes the engine controller and wiring harness. For an EFI engine, confirm both items in the exact included-parts list and check that they match the engine and transmission. An installed intake manifold or fuel system does not establish that the electronics are included. Ford’s Gen 4X crate-engine page, for example, directs buyers to matching control packs. Our Coyote swap guide explains the other items to check before choosing a package.
Is a long block a complete engine?
No. A long block is the core of the engine, but it needs an intake, fuel system, ignition and accessories before it can run.
What is a long block engine?
A long block engine is a short block (the block, crankshaft, connecting rods and pistons) with the cylinder heads and valvetrain fitted, so the core of the engine is complete. It usually does not include the intake manifold, fuel system, ignition or accessories, so it needs those parts before it can run. Included parts vary by package, so check each listing in our crate engines category.
New to crate engines? Read what a crate engine is and how to choose one. Before the first start, read how to break in a new engine.
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