The LS1 and LS2 engines are both part of the LS family of engines, but they have some key differences. The LS1 was introduced in 1997 and has a displacement of 5.7 liters, while the LS2 was introduced in 2005 and has a displacement of 6.0 liters. The LS2 has a higher power output than the LS1, thanks to a larger displacement and other improvements. The LS2 also has an improved cylinder head design, larger intake valves, and a more aggressive camshaft profile.