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Gen 4 LS Engines - Junkyard LS Swap Identification Guide: Part 2


In the second installment of our junkyard LS swap identification guide I am going to talk about the Generation 4 small block series of V8s that share the same platform as the Generation 3 discussed previously.

GM ultimately made some changes to their new popular LS series and thus the Generation 4 small block was born. Taking many of the same forms, with some slight differences in naming and technology changes, the same platform was carried on to later years of production spanning from about 2005-2014. Though, there were a few years of crossing over all of the vehicle platforms.

The LS2 would become the performance version of the prior 6.0 truck engines – this time featuring an aluminum block, LS6 heads, and a performance camshaft. The LS2 netted right around 400hp/400tq respectively. You can find the LS2 in C6 Corvettes, 05-06 GTO, Cadillac CTSV and Chevy Trailblazer SS models. Now just like the other performance LS style motors; these can be tricky to find if you are searching your local junkyard and they usually come with a pretty hefty price tag.

The 4.8L/5.3L version would carry on in Gen 4 found in two combinations; the aluminum block LH6/LC9 models and the iron-block versions known as LY5/LY2/LMG/L20 engine code names. Gen 4 versions of the 4.8/5.3L engines did see a slight increase in horsepower and torque numbers because of improvements in combustion ratios and better fuel mileage in their factory trims, netting around 300hp/320tq. It should be noted that GM had made some substantial changes in the electronics and fuel injection components to Gen 4 truck engines and they do not interchange with Gen 3 engines easily.

*GM did make a 5.3L LS4 model that was found in a limited run of FWD applications and must utilize a different mounting style and transfer case. For the most part, this is not an engine choice for almost any of the swap projects we normally see in the hotrod community.

LY6/L76 iron truck engines would continue on with the 6.0L being offered in various GM truck and SUV models, with slightly lower horsepower and torque numbers than the LS2 variant. They produced around 370hp and 400tq in stock trim.

The Gen 4 engines, because they are newer, are going to cost more and require more of the correct OEM electronics to run properly. That should be considered when finding these for a potential swap project. To put it simply, the Gen 4 motors had newer, more modern technology, which in turn requires more sensors, computers, and wiring harness to run all the electronically controlled systems. You definitely want to make sure you are getting as much of the wiring and electronics as possible when sourcing your Gen 4 pullout engines.

On the surface this all can look like a lot of work, but once you see how well these engines perform you will never look back at the old tried and true days of small blocks and carburetors. Part of the fun of doing this is sometimes seeing just how far you can stretch your dollars and be able to have some fun in your ride. The allure to this whole madness is making as much power as you can out of something you scrapped together from a few junkyards and local deals with the car crowd.

If the junkyard isn’t for you, then luckily there are plenty of crate motor options for those that have the funds and don’t want to fool around with finding all the right pieces to their LS engine puzzle. Numerous aftermarket and OEM manufacturers are building some really stout and reliable LS based crate motors, such as the GM Performance LS3 Crate Motor, P#35519301326. Literally drop it in to your project and have 430 hp at your disposal. I was lucky enough to run back to the warehouse and pop open one of these trick LS3 crate motors and snapped a few pictures as well.

Unfortunately, this guide still doesn’t cover all the variations of this platform of engines that has been produced over time. I focused more on the common, cheaper alternatives when considering making the switch to LS power. Being able to put together a combination that performs using this modern V8 platform creates a fun challenge in itself and in most cases is a cheaper alternative to other options. We all would love to be able to drop a fresh crate LS motor into our latest project – but for most of us that just isn’t a reality unless we saved for years and years. Part of the car culture addiction stems from the ability to be frugal and inventive in our quest for more fun behind the wheel.

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