Intro to the LH6, LC9, LH8, and LH9

LH6

The LH6 replaced the LM4 in 2005. It was the first Gen. 4 LS truck engine and offered Active Fuel Management (AFM). The LH6 was available in GM mid-size SUVs until 2009. It was also available in GM pickups from 2007-09. It was known as the Vortec 5300.

LC9

The LC9 was introduced in 2007. Originally, it was a flex fuel version of the LH6. In 2010, the LC9 was upgraded with Variable Valve Timing (VVT) and replaced the LH6. It was available in GM pickups and SUVs until 2014. The LC9 was also known as the Vortec 5300.

LH8

The LH8 was introduced in 2008 as the V8 option for the Hummer H3. It was the most basic engine of its family. It did not use any special technology. The LH8 was available in the H3 and GM mid-size pickups through 2009. It was also known as the Vortec 5300.

LH9

In 2010, the LH8 was replaced by the LH9. The LH9 was upgraded with VVT and flex fuel capability. It was available in the H3 for 2010. It was also available in the mid-size pickups until 2012. Like the other 5.3L engines, it was known as the Vortec 5300.

For specific details about each of these engines, please follow the links below:

• Chevy LH6 Engine Specs
• Chevy LC9 Engine Specs
• Chevy LH8 Engine Specs
• Chevy LH9 Engine Specs
• Upgrading the LH6, LC9, LH8, and LH9 Engines

Benefits

These engines were some of the first Gen. 4 LS engines. The LH6 was released at the same time as the LS2 and is very closely related. All the engines in this family have the same 799 or 243 cathedral port heads that came on the Corvette's LS6 and LS2.

The 5.3L engines have a smaller 3.780 in. cylinder bore. This means the cylinder walls are thick, adding strength and rigidity. They can be bored to the LS1 size (3.898 in. +). But, if you plan on using boost, a smaller bore will keep the block strong.

The aluminum blocks are lightweight, compared to similar iron block engines. Just like all the Gen. 4 engines, the blocks have internal oil passages for AFM, even if it wasn't used. With upgraded internals, they can handle around 850 hp.

What's the difference?

The easiest way to tell the difference is to check the 8th digit of the VIN code.

• Follow this link to Identify an LS Engine by VIN.

The difference between the engines is the special technology used on each one.

• Follow this link to Identify AFM.
• Follow this link to Identify VVT.
• For fuel compatibility, you can pull the injectors.
• • Standard injectors had 2 holes on the end of the nozzle.
  • Flex Fuel injectors had 4 holes on the end of the nozzle.

​​​Special Notes

• All 2005-06 LH6 engines had the 24x reluctor and 1x cam gear, like the Gen. 3 engines.
• Everything produced in 2007 or later had the standard Gen. 4 58x reluctor and 4x cam gear.