L59 Vs. LM7 Engine : What’re the Differences?

L59 Vs. LM7 comparison constantly surfaces when GM fans sit to analyze some of the auto manufacturer’s most durable engines since its inception. Although the engines were released at different times, they seem to have a few similarities.

However, some vehicle enthusiasts claim the L59 is better, while others disagree with this notion. Nevertheless, these two engines have been carefully analyzed in this review in order to clear the air about their similarities and differences.

After going through this post, you will be able to ascertain the difference between the L59 and the LM7 with uncanny precision.

L59 Vs. LM7 Engine

L59 Engine

The L59 is a solid 5.3L Gen. 3 engine designed by General Motors and released in 2002. The iron-block engine was built to accommodate flexible-fuel type while serving as an upgraded version of its LM7 counterpart.

The engine could run using gasoline and E85 fuel. GM features the L59 in most of their SUVs and pickup trucks between 2002 and 2007. This engine was popularly referred to as Vortec 5300. It had the VIN code “Z” at the 8th position of the VIN number.

The L59 was a member of the 3rd generation LS family. The engine was built with sophisticated features, including horsepower and torque output. In addition, the iron casting provided a strong capacity to withstand the limitations of its aluminum engine counterparts.

Some of the GM product lines that were built with the L59 include the GMC Yukon & Yukon XL 1500 (2002 – 2006 models), Chevy Suburban & Tahoe (2002 – 2006), GMC Sierra 1500 (2002 – 2007 models), and Chevy Silverado & Avalanche Z71 (2002 – 2007).

Read Also: LS3 vs. LS7 Engine: What’re the Differences?

LM7 Engine

The LM7 engine was also built by GM; however, it was released in 1999 before the L59 was considered to introduce in the market. Like the L59, the LM7 engine was also referred to as Vortec 5300.

The engine was fitted in most of GM’s SUVs, vans, and pickup trucks from the engine’s inception period till about 2007. The iron-block engine was also from the LS family lineage, with some slight differences from its counterparts.

The LM7 VIN code is tagged “T” at the 8th position of the VIN number. LM7 engines were available in Chevy Silverado 1500 & GMC Sierra 1500 (1999 – 20006 models), GMC Yukon & Chevy Tahoe (2000 – 2006 models), and GMC Savana & Chevy Express (2003 – 2006 models).

Apparently, most of the GM trucks had L59 and LM7 engines within the same period. However, the flexible fuel types used in the trucks with L59 engines were the main difference between these vehicles. In addition, a few more differences are captured in the next section.

Read Also: LS1 vs. LS6 Engine: What’re the Differences

LM7 Vs. L59 Differences

The LM7 and L59 are identical in many aspects, especially when you try to judge by their physical appearances. However, an in-depth look into their make-ups, capacity, and other intangible features will help you discern the difference between LM7 Vs. L59 engine.

Nonetheless, even though they both belong to the LS family, the comparison table below unveils the main differences between the LM7 and the L59 engines.

Specifications: L59 LM7
Manufacturing date  2002  1999
8th digit VIN Code  Z T
Horsepower Output  285 – 295 horsepower  270 – 295 horsepower
Torque Output 320 – 335 ft-lbs 315 – 335 ft-lbs
Uniqueness  Flexible fuel Low emissions
E85 Usage Yes No

L59 Vs. LM7 HP

Although the L59 and LM7 engines are products of the same lineage, built with similar physical structures, they possess slightly different performance capacities. The L59 was built with a whooping 285 – 295 horsepower alongside 320 – 335 ft-lbs torque output.

On the flip side, the LM7 engine offers 270 – 295 horsepower and 315 – 335 ft-lbs torque output levels. Although the horsepower difference is minute, the L59 was designed with slightly better performance than its LM7 brother.

L59 Vs. LM7 Injectors

The L59 engine uses EV6 / USCAR injectors. The injectors are designed with the capacity to accommodate the corrosive nature of E85 fuel. They are built with a relatively higher flow rate.

The L59 engine comes with a PCM program that easily identifies E85 or direct gasoline by monitoring the oxygen content that is specific to both fuel types via the O2 sensor.

Conversely, the LM7 uses Multec injectors. The LM7 injectors can only accommodate direct gasoline as against the L59 which allows both gasoline and E85. Therefore, their flow rate is relatively lower than that of the L59 injectors.

However, irrespective of these slight differences, an L59 to LM7 swap is still possible. All you need is to harvest the sensor, rail, and injectors, among other components, from the L59 to the LM7.

Nevertheless, ensure to contact your auto mechanic for professional advice if you’re considering a swap between the two engines. However, this is not a DIYer league; except you’re sophisticated enough to conduct the swapping exercise.

Read Also: LLY Vs. LBZ – A Comparison of Two Best


Q: Are L59 engines good?

Sure, L59 engines are some of the most famous LS engines. The Gen. III 5.3L engines are topnotch because of their iron-block strength and nitrous application, among other awesome L59 specs. No wonder they were used in GM SUVs and trucks from 2002 – 2007.

The L59 engines were equipped to deliver up to 285 – 295 horsepower and 320 – 335 ft-lbs, respectively. They were typically another version of LM7 with flexible fuel operations.

Some of the vehicles that enjoyed the awesomeness of the L59 include the GMC Yukon, Chevrolet Suburban, Chevrolet Tahoe, Chevrolet Avalanche Z71, GMC Sierra 1500, Chevrolet Silverado 1500, etc.

Q: How much power can L59 handle?

L59 engines are built with the capacity to handle more than 1,000 horsepower (HP) with their nitrous application. However, this power output level requires upgrading a few components like the cold air intake, cylinder heads, fuel system, etc.

More power means more responsibility for the engine, hence the need to upgrade some of the mechanical components that will enhance the engine’s performance.

If you desire a power boost in your L59 engine, kindly ask an expert auto mechanic what it will take to get an upgrade. However, it is important to note some of the L59 engine problems and figure out how to curb them.

Q: How much horsepower does an L59 have?

An L59 engine is equipped with 285 – 295 horsepower output and 320 – 335 ft-lbs torque output, respectively. The 9.5:1 compression ratio also assists in the engine’s overall performance.

With the kind of horsepower level the L59 delivers, its work potential is pretty remarkable. It is obvious that L59 upgrades are geared toward making the engine outstanding because they already have a good base.

Q: How much hp does an LM7 have?

An LM7 engine is built with 270 – 295 horsepower output and 315 – 335 ft/lbs torque output, respectively. It also features a similar compression ratio to its L59 counterpart. Again, just like the L59, the LM7 can handle more than 1,000 horsepower with the proper upgrade systems.

Although the L59 and LM7 have some slight differences, the engines are built with the capacity to handle more power for improved performance. However, boosting the engines come with a cost that you must budget appropriately.

Q: Is LM7 aluminum or iron?

The LM7 is an iron-block engine like its flex-fuel L59 counterpart. The 5.3L Gen. III engine is built with GM’s sophisticated architecture to provide strength, power, and performance.

Besides the material, the LM7 engine block specification is very robust with a 3.780 inches bore diameter, 3.622 inches stroke, 9.230 – 9.240 inches deck height, 4.400 inches bore spacing, etc. No doubt, iron block engines are relatively stronger than their aluminum counterparts.

Q: Is LM7 a long block?

Of course, the LM7 is a long block in the Gen. III LS family. This is an obvious similarity if you’re considering the L59 engine Vs. LM7 comparison. Although the LM7 was released in 1999 and its L59 counterpart was released in 2002, the latter is simply a flex-fuel vehicle version of the former.

In any case, the LM7 is an amazing engine from GM’s product line. Since its inception, vehicle enthusiasts never fail to rate it as one of GM’s most remarkable releases at that time. Its long block and other sophisticated features made the LM7 a hot cake for most of GM’s trucks.

Final Words

Separating the features of the L59 and LM7 engines are quite tricky indeed. Nevertheless, looking away from the external features to the intangible aspects of the engines will do the magic.

Therefore, analyzing both the engines to solve L59 Vs. LM7 debate requires observing the 8th digit VIN number/code, the fuel type compatibility, and a few other internal features.

Indeed, choosing between the two engines can be somehow difficult, especially due to the fact that LM7 may not accommodate E85, and L59 may come with some side effects such as excessive oil consumption and a host of others. All the same, your priorities will determine which of the engines is best for you and there is no clear winner between them.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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