The General Motors 60° V6 engine family is a series of 60° V6 engines produced for both longitudinal and transverse applications. All of these engines are 12-valve cam-in-block or overhead valve engines, except for the LQ1 which uses 24 valves driven by dual overhead cams. These engines vary in displacement between 2.8 and 3.4 litres and have a cast-iron block and either cast-iron or aluminum heads. Production of these engines began in 1980 and ended in 2005 in the U.S., with production continued in China until 2010. This engine family was the basis for the GM High Value engine family. These engines have also been referred to as the X engines as they were first used in the X-body cars.

The High Value engine family from General Motors is a group of cam-in-block or overhead valve V6 engines. These engines feature cast iron blocks and aluminum heads, and use the same 60° vee bank as the 60° V6 family they are based on, but the new 99 mm (3.90 in) bore required offsetting the bores by 1.5 mm (0.059 in) away from the engine center line. These engines are the first cam-in-block engines to implement variable valve timing, and won the 2006 Breakthrough Award from Popular Mechanics for this innovation. For the 2007 model year, the 3900 engine featured optional displacement on demand or "Active Fuel Management" which deactivates a bank of cylinders under light load to increase highway fuel economy. It was rumored that GM would produce a 3-valve design, but that never came to be. These engines were produced primarily at the GM factory in Tonawanda, New York, and at the Ramos Arizpe engine plant in Mexico. The assembly line for this engine was manufactured by Hirata Corporation at its powertrain facility in Kumamoto, Japan.