Engine Long Block

What Is an Engine Long Block?

An engine long block is one of the most comprehensive engine assemblies you can buy short of a fully dressed, ready-to-run motor. It typically includes the engine block, crankshaft, connecting rods, pistons, camshaft, cylinder head(s), and valve train — essentially everything from the oil pan to the valve covers. What it does not include are the external accessories: intake manifold, exhaust manifolds, carburetor or fuel injection system, ignition components, and ancillary brackets.

This makes a long block the ideal starting point for a comprehensive engine rebuild or swap. You supply the fuel delivery and ignition hardware you already own (or prefer), and the long block provides the precision-machined heart of the powertrain. Whether you are replacing a worn-out original, building a performance street machine, or constructing a custom motorcycle from the ground up, a long block dramatically shortens build time compared to assembling individual components from scratch.

Why Choose a Long Block Over a Short Block?

A short block gives you the lower end of the engine — block, crank, rods, and pistons — but leaves cylinder head selection entirely up to you. A long block goes further by including the fully assembled cylinder head(s) and valve train. This is a significant advantage: cylinder head porting, valve sizing, and camshaft selection are among the most influential factors in an engine's power characteristics, and a matched long block ensures those components are designed and tested to work together from the factory floor.

For builders who want maximum control over intake, exhaust, and ignition tuning but prefer not to source and machine individual internal components, a long block strikes the perfect balance between convenience and customization.

Key Considerations When Shopping for a Long Block

• Application compatibility: Confirm the long block is engineered for your specific vehicle platform, chassis type, or model year range.
• Displacement and performance level: Long blocks are available from stock-replacement specs all the way to high-displacement performance builds. Match the engine's output rating to your drivetrain and intended use.
• Finish and break-in requirements: Some long blocks are fully assembled and ready to drop in; others require a careful break-in procedure. Review the manufacturer's guidelines before first startup.
• Warranty coverage: Reputable manufacturers back their long blocks with meaningful warranties — a strong indicator of build quality.

Top Engine Long Block Brands

BluePrint Engines is a well-respected name in the crate and long block engine market, known for producing high-quality American V8 and performance engines built to precise tolerances. Their long blocks are popular among hot rodders and engine builders who want a reliable, dyno-tested foundation for everything from street drivers to track builds.

S&S Cycle is the benchmark for aftermarket motorcycle long block engines, with decades of experience building high-displacement V-twin powerplants for Harley-Davidson platforms. Built in Wisconsin, S&S T-series long blocks bolt into Twin Cam Dyna, Softail, and Touring chassis and come with the hardware the swap requires. Their V111 long block, for example, delivers a genuine 30% power increase over stock while maintaining reliability through a short-stroke design.

EMPI has long been a trusted supplier of Volkswagen air-cooled engine components and complete long block assemblies. Their VW-based long blocks are a go-to choice for Beetle, Bus, and dune buggy enthusiasts who need a straightforward, affordable engine core that retains the classic air-cooled architecture.