When an engine fails catastrophically, sometimes replacing the entire "Cardio-Pack" (a pre-assembled block with pistons and crankshaft) is faster and cheaper than a piece-by-piece rebuild.

These pre-assembled lower blocks, commonly known as short blocks, come directly from the manufacturer with the rotating assembly already balanced and torqued to perfection. For fleet managers, buying a short block eliminates the downtime and variables associated with sending the old block to a machine shop. The mechanics simply transfer the cylinder head, oil pan, and fuel injection system from the old engine to the new power pack, cutting repair times by more than half.