The LS6 is a higher-output version of GM's LS1 engine and retains the same capacity. The initial 2001 LS6 produced 385 hp (287 kW) and 385 ft·lbf (522 N·m), but the engine was modified for 2002 through 2004 to produce 405 hp (302 kW) and 400 ft·lbf (542 N·m) of torque. The LS6 was originally only used in the high-performance C5 Corvette Z06 model, with the Cadillac CTS V-Series getting the 400 hp engine later. The V-Series used the LS6 for two years before being replaced by the LS2 in 2006. For 2006, the Z06 replaced the LS6 with the new 7.0L LS7.

The LS6 shares its basic block architecture with the GM LS1 engine, but other changes were made to the design such as windows cast into the block between cylinders, improved main web strength and bay to bay breathing, an intake manifold and MAF-sensor with higher flow, a camshaft with higher lift and more duration, a higher compression ratio, sodium filled valves, and a revised oiling system better suited to high lateral acceleration. [1]

The casting number, located on the top rear edge of the block, is 12561168.

Applications:

* 2001-2004 Chevrolet Corvette C5 Z06
* 2004-2005 Cadillac CTS V-Series