Generation III LQ4The Vortec 6000, or LQ4, is a V8 truck engine. Displacement is 6.0 L (366 cu in) from 101.6 mm bore and 92 mm stroke. It is an iron/aluminum (2000 model year engines had cast iron heads) design and produces 300 horsepower to 325 horsepower and 360 lb·ft to 370 lb·ft .