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The LS2 engine was General Motors’ first engine in its Generation IV family for its small block V8 engines. This engine was created with a volume of 5.967 L, or more generically 6.0L, slightly larger than the 5.7L LS6 engine that it replaced in several models.
The Gen IV offering was still very similar to the Gen III, as the possibility for interchanging parts between the Gen III and Gen IV engines exists in quite a few cases, but be sure to do your homework before just substituting parts.
Gen III vs Gen IV
One of the primary distinctions for the Gen IV engine is a generally larger bore. This fact reduces the exchangeability of heads between Gen III and Gen IV engines as a Gen IV head may have valve interference with the narrower blocks from the Gen III platform.
Another major difference is the block modifications for the Gen IV engines that enable the use of active fuel management, or sometimes known as displacement on demand, which is the ability to only use certain cylinders in scenarios where full performance is not required, such as highway cruising.
The LS2 was first offered in 2005 to customers as the base model for the Corvette, Chevrolet SSR and Pontiac GTO, in addition to some models offered only outside of North America. The LS2 was then also offered in 2006 in the Chevrolet Trailblazer SS and the Cadillac CTS-V series. In 2008 the Saab 9-7x Aero also added the LS2 option.
As mentioned, the LS2 offering was primarily started in 2005 with some additional options in 2006. The LS2 engine did not stay around too long, as it was only available in the Corvette until 2007, while the Saab and Trailblazer SS models kept this as an offering until 2009. The LS2 is no longer in regular production but is without a doubt still widely used and retrofitted in many project cars.
With the larger displacement and higher compression ratio, this engine provided the ability to achieve more power, although there are other limitations in some cases which can help explain the slight reduction in power when going from the LS6 in the Corvette Z06 to the LS2 in the base model Corvette.
Horsepower, Torque and Displacement
The LS2 was rated at 400 horsepower at 6000 RPM, while rated torque is 400 lb-ft at 4400 RPM. While the torque number matches peak torque from the LS2, it is reached 400 RPM lower, which certainly improves the feel of the engine. The 6.0L engine displacement, when converted to cubic inches as is more common to some, comes out at 364 cubic inches.
As mentioned, this bore is slightly larger compared to its Gen III predecessors, with the bore coming in at 4.00 inches with a stroke of 3.62 inches. Other performance improvements with the LS2 can also be attributed to its increased compression ratio of 10.9:1, in comparison with the 10.5:1 ratio from its predecessor, the LS6.
Block and Heads
The LS2 engine is only offered with an aluminum block and cylinder head. The pistons are constructed of hypereutectic aluminum alloy, as is common with almost all of the LS engine family. The pistons used employ a flat top design. The hypereutectic construction reduces the thermal expansion of the piston and allows for a tighter fit in design between the cylinder and the piston. The LS2 uses a conventional push rod overhead valve (OHV) valve train. The valve architecture uses 2 valves, 1 intake and 1 exhaust per cylinder.
The LS2 introduction marked the introduction of the General Motors Gen IV short-block V8 series. This platform allowed for more power and the addition of other improvements such as active fuel management. This 400 horsepower engine was first introduced in the base model for the Corvette, and then also made available in other performance driven vehicles. Overall this engine was available in normal production from 2005 until 2009.