A long block engine is an engine assembly that includes more parts than a short block engine. It is assembled with the crankshaft, connecting rods, pistons, bearings, and rings, just like a short block engine, but it also includes the cylinder heads, camshaft, and valve train. In some cases, a long block engine may also come with an oil pan, water pump, and valve covers. Long block engines are generally more expensive than short block engines, but they offer better reliability and performance. They are a good option for situations where a vehicle needs a complete engine overhaul. On the other hand, short block engines are less expensive and come with a shorter list of components, usually including only the engine block, crank, pistons, and connecting rods. Short blocks may also include other items such as the camshaft, timing chain, and covers. Short block engines are a good option if you have cylinder heads that you want to use or if you prefer to customize the engine on your own.