LH9 5.3L Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More

The LH9 engine is a 5.3L, Gen. 4, aluminum small block engine used in GM trucks and SUVs between 2010-2012, including the 2010 Hummer H3.

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.

The engine specs and information listed here is for a stock LH9 engine.

Mechanically similar, General Motors’ LS and LS-based Vortec engines wound up on almost every branch of the GM family tree: Chevy, Pontiac, GMC, Cadillac, Buick—heck, even Saab, Hummer, and Isuzu got some LS love.

Since LS and Vortec engines are so common, they’ve become the go-to performance and swap engines of the modern era.

These motors are capable of making a lot of horsepower, and respond well to upgrades like turbos, superchargers, high-flow cylinder heads, intake systems, cams, and nitrous oxide.

[Looking to upgrade your LH9 engine? Check out LH9 5.3L Engine Upgrade Guide: Expert Advice for LH9 Mods to Maximize Performance.]

The aftermarket is strong, crate engines are available, and used motors are often cheaply sourced through junkyards.

Summit Racing has created a series of comprehensive guides for each engine in the LS family, so engine builders and tuners can have a handy reference for their projects.

This specific guide is for the GM LH9 5.3L engine.

You can find more LS engine spec guides and LS-related information here.

(Summit Racing’s Paul Spurlock and Brian Nutter contributed to this article.)

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LH9 5.3L Engine Specs

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NOTE: You can find engine specs and detailed engine upgrade advice for every LS and LS-based Vortec truck engine in one place: The Definitive Guide to LS Engine Specs and LS Engine Upgrades.