The LS7 shares the architecture which debuted with the celebrated LS1 in 1997, maintaining the LS1/2/6 engines' external dimensions, though nearly every component is all-new or revised for durability and power production. The block is a unique casting, designed to accommodate the 4.125-inch bore pressed-in dry cylinder liners. Main caps have been upgraded from the powdered metal material to forged steel, located and retained by dowels and six fasteners at each cap. That's some serious structure downstairs. Final block machining is carried out with torque plates installed, and main bulkhead fasteners torqued to specs.