A Wisconsin long block is a low cost alternative to replacing the complete engine and is especially practical when all your external components are in good condition. A long block is manufactured by and supplied by the factory. Basically they make a standard engine production run and pull them off the line before they start attaching all the external components. This guarantees consistent quality.
A long block assembly is made up of the following components;
1) crankcase, cylinder barrels and heads
2) front and rear main bearing plates
3) pistons, rings, crankshaft, camshaft, valves, guides, etc
4) all is assembled complete ready to transfer over your old components and they include all the gaskets you require to install your magneto or distributor drive, carb, fuel pump, intake and exhaust manifold, etc.
A short block assembly is the same item as detailed above but does not come cylinder heads. All required gaskets are also supplied with a short block.