It has a displacement of . The compression ratio was 9.9:1 for 2010, but was reduced to 9.7:1 for the remaining two years of production. LH9 applications:   The LS4 is a version of the Generation IV block. Though it has the same displacement as the Vortec 5300 LY5, it features an aluminum block instead of iron, and it uses the same cylinder head casting as the Generation III LS6 engine. The bellhousing bolt pattern differs from the rear-wheel drive blocks. This engine is adapted for transverse front-wheel drive applications. According to GM, "The crankshaft is shortened at the flywheel end and at the accessory drive end – to reduce the length of the engine compared to the 6.0 L. All accessories are driven by a single serpentine belt to save space. The water pump is mounted remotely with an elongated pump manifold that connects it to the coolant passages. Revised oil pan baffles, or windage trays, are incorporated into the LS4 to ensure that the oil sump stays loaded during high-g cornering." Active Fuel Management is also used. Output of this version is /300 hp on LaCrosse Super and . Applications:  Inspired by the LS1.R in size and performance goals, this family of blocks was designed for race oriented performance. The only engine with this bore size that was used in a production vehicle is the LS7 with the LSX being only for aftermarket use. One unique feature of this family is that the cylinders are siamesed, no water passages between neighboring cylinders. This was done to increase both bore size and block strength. LS7  The LS7 is a engine, based on the Gen IV architecture. The block is changed, with sleeved cylinders in an aluminum block with a larger bore and longer stroke than the LS2. The small-block's bore spacing is retained, requiring pressed-in cylinder liners. The crankshaft and main bearing caps are forged steel for durability, the connecting rods are forged titanium, and the pistons are hypereutectic. The two-valve arrangement is retained, though the titanium intake valves by Del West have grown to and sodium-filled exhaust valves are up to . Peak output is at 6300 rpm and of torque at 4800 rpm with a 7000 rpm redline. During GM's reliability testing of this engine in its prototype phase, the LS7 was remarked to have been repeatedly tested to be 8000 rpm capable, although power was not recorded at that rpm level, due to the constraints of the camshaft's hydraulic lifters and the intake manifold ability to flow required air at that engine speed.