​​How Much HP Does A LQ9 Engine Have & Which Cars Have One Under The Hood?

The third generation GM small block is one of the most famous engine series under the sun, and for good reason. The third-gen's strength, power, and versatility took the GM small block to heights that had never been reached before and that's saying something, as the first two generations contain some of the most celebrated V8s in American history, including the 350 and LT1. Between 1997 and 2007, the third-generation small block was offered in multiple displacements and across a wide range of GM vehicles, from sports cars to heavy-duty trucks. It is often the LS variants that get the most props, since they were found in more interesting cars like the Corvette and Camaro. However, the truck variants of the Gen III small block, often referred to as "Vortec" engines, are just as formidable in truck applications.

The LQ9, sometimes called the Vortec HO 6000, is a high-output 6.0-liter variant of the Gen III GM small block that was used in a variety of large GM SUVs and trucks from 2002 to 2007. Like the rest of the Vortec engines, the LQ9 shares a very similar design to the LS engine series, but with a cast iron block and other strengthening improvements. The LQ9 is very similar to the widely used 6.0 liter LQ4 V8 built by GM from 1999 to 2007. The LQ9 was meant to be the high-performance version of the LQ4 for use in top-tier SUVs and trucks, so it received a more aggressive camshaft, aluminum cylinder heads, and 10.0:1 flat-top pistons. Those improvements raised the LQ9's output to 345 horsepower and 380 lb-ft of torque.

Being the high-output version of the Vortec 6.0L, the LQ9 was reserved for only the best trucks and SUVs that GM had on offer from 2002 to 2007. The majority of lower-tier truck and SUV options utilized the LQ4. Initially, the LQ9 was designed for the Cadillac Escalade, which debuted in 1999 as an upscale version of the GMC Denali. The Escalade was scrapped after the 2000 model year but brought back for 2002 when the LQ9 made its first appearance. The LQ9 remained a fixture in the Escalade from 2002 until 2006, used in the standard, EXT, and ESV trim levels. Following its use in the Escalade, the LQ6 found its way into the Chevy Silverado SS in 2003. The Silverado SS was Chevy's entry into the 2000s muscle truck craze, taking the fight to Dodge and Ford with their SRT-10 and Lightning pickups. While the LQ6's 340 horsepower and 380 lb-ft of torque were respectable, its output was no match for the 500 horsepower Viper V10 in the SRT-10 or the supercharged 5.4L V8 in the Lightning, banishing the Silverado SS to relative obscurity.

While the Silverado SS was around until 2007, GM started putting the LQ9 into other light-duty trucks that didn't bear the legendary SS badge as early as 2004. It was offered in both the standard Chevrolet Silverado 1500 and GMC Sierra as the "high-output" package between 2004 and 2006 with the 4L65E transmission and Z85 sport suspension also included. For 2006 and 2007, the LQ9 package was renamed VortecMAX and was reworked to include improved towing suspension and stronger rear axle.