When seeking the definition of short blocks and long blocks, the answer is fairly simple. The main difference between a short block and a long block is the number of parts included and assembly completed. While a short block assembly is comprised of the engine block with assembled rotating assembly (crankshaft, connecting rods, and pistons), a long block includes assembled cylinder heads and valvetrain and can include additional external engine components.
What Is A Short Block?
When comparing a short block vs long block, a short block is an engine block assembled with the crankshaft, connecting rods, bearings, pistons, and rings installed at a minimum. Some short blocks may include additional parts such as a camshaft with timing set installed as well as an oil pump and pan. However, a short block will not include the cylinder heads or anything assembled above the engine block deck.
What Is A Long Block?
A long block is an engine assembled with the crankshaft, connecting rods, pistons, bearings, and rings. In addition to the short block, cylinder heads and the valve train, including the camshaft, are included in a long block. Another way to explain a long block is that all of the internal mechanical / moving parts of an engine are included and assembled. Some long blocks also include the valve covers, oil pan, and timing cover. Others will include additional parts such as the intake manifold, or even the carburetor, distributor, balancer, water pump, and more. Typically, those engines are referred to as “dress” or “turn-key” crate engines as more parts are included than a standard long block.
Which Type Should I Buy, short block or long block?
There are a few things to consider when deciding between a short block or long block. If you do not have any components for the engine you want in your vehicle, either option can be used. However, if you have cylinder heads that you want to use, then the short block would be the way to go. A long block may be the clear choice if it has everything you are looking for and that you like. 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. In the end, it comes down to how much work you want to complete on your own, your budget, and the parts you want included.
