When talking about replacing an engine the terms “short block” and “long block” are often tossed around. Short and long refer to the completeness of the block rather than the size. Short blocks don’t have as many internal parts included compared to long blocks.
A short block is not complete but it does come with a crank, pistons, and connecting rods. More parts are required such as cylinder heads, gaskets, an oil pump, etc. Since the short block isn’t complete, it gives you the opportunity to make it what you want. You can complete the block with higher quality parts to enhance engine performance. A lot of car owners choose a short block specifically for that reason.
A long block is more complete leaving less room to customize the engine build. What is included in a long block is the crankshaft, cylinder heads, valve train, camshaft, intake manifold, oil pan, and all covers.
So in what situation would you pick one over the other? It depends on your goal. Maybe you’re looking to get better performance out of your vehicle for the track and you have some upgrades in mind to do that. Then a short block would be your answer. Let’s say that you’re fine with the stock internals of the long block and you just need your engine replaced. This would be a case for a long block. It’s also quicker to install a long block because there’s less work that needs to be done. However, that is not to say that long blocks are inadequate for high performance vehicles. You can still make big power with power-adders like a supercharger with a long block.
