7 GM LS & LT Crate Engines You Should Consider For Your Next Build

LS— and soon to be LT— engines are seemingly ubiquitous these days. Not only can you find them under the hood of most V8-powered GM vehicles, they have been hitting the streets since their introduction in the 1997 Corvette. This means that there is a menagerie of LS, or LS-based, options sitting around in junkyards and classifieds across the nation. And while junkyard builds can be awesome, sometimes you don’t want the hassle, or inherent risk, of resurrecting previously-loved LS engines. Plus, sometimes you want to get your hands on a direct-injected LT1 right away instead of waiting for some poor schlub to wrap it around a tree or put hundreds of thousands of miles on it.

Engines Highlighted

  • LS3
  • LS376
  • LSX376
  • LS7
  • LSA/LS9
  • LT1
  • LT4

One company – Pace Performance – specializes in LS and LT crate engines. Greg Was from Pace helped us put together this list, and gave us some feedback and guidance on what crate motors are the most popular and why along the way. 

With that in mind, we thought we’d provide a rundown of the seven best LS (and LT) crate motors that should be considered for your next build; in the off chance that you just want to drop something straight in and go. While we understand that most of these crate engines are not exactly cheap, for those who want to make reliable power without the headache of sourcing, machining and rebuilding, these crate motors make a powerful (literally) argument.

LS3CoyoteShootout

The LS3 is the go-to choice for LS engine swappers right now and for good reason; this mill makes great power and is about as reliable as they come. This example, from our LS3 vs. Coyote shootout, made 556.3 hp at 6,500 rpm and 497.2 lb-ft of torque at 5,500 rpm.

1. LS3

Chevrolet Perfomance— PN 19301362

For those that want a turn-key crate engine, it is hard to go wrong with the tried-and-true LS3. The gen-IV small-block produces 430 horses at just 5,900 rpm and 425 lb-ft of torque at 4,600 rpm— a solid performer for any project. Just ask the producers of “Fast and Furious 7,” as Mighty Car Mods discovered, every car built for the film utilized a 500-horse version of the LS3 under the hood.

Chevrolet Performance also offers the LS3 in E-Rod trim, which is 50-state emission legal and comes complete with exhaust manifolds, catalytic converters, oxygen sensors, EVAP canister, MAF sensor, accelerator pedal and pre-calibrated ECU. The motor also has room for improvement if you aren’t satisfied with its current power production, but if you are thinking of adding boost to the equation, you may want to consider other versions covered in this list.

“The LS3 is definitely one of our most popular crate motors,” said Greg Was, from Pace Performance. “I think most people choose it because of the different configurations it comes in, specifically the Connect & Cruise version.”

Cost: $7,911

LS376:515

The CT525 and LS376/515 does away with the standard fuel-injection intake manifold in favor of a carbureted setup.

2. LS376 480/525

Chevrolet Performance — PN 19301358 and 19301360

The LS376 is basically a spiced up LS3 and comes in two power levels: the 480, which adds Chevrolet Performance’s LS Hot Cam to the mix resulting in 495 horsepower and 473 lb-ft of torque, and the 525, which utilizes Chevrolet Performance’s more aggressive ASA camshaft to produce 525 horsepower.

“We typically recommend the 480-horse version,” Was said. “It is a little better for a street car, it has a lot better street manners.”

The LS376/525 also comes in several other iterations:

  • DR525— While this motor has the exact same specs as the LS376/525, this is a factory-sealed motor that is designed as the spec engine for the National Muscle Car Association’s LS Stock racing class.
  • LS376/515— This model swaps out the LS’s fuel-injection intake manifold in favor of a carbureted setup, for a more retro look. It also produces eight more ponies than its fuel-injected brother.
  • CT525— This version is basically the 515 but specifically tailored for circle track racing by utilizing an 8-quart circle track oil pan.

Cost: $8,438 and $9,698

LSX376B8

With its iron block, the LSX376-B8 is built for boost.

3. LSX376

Chevrolet Performance— PN 19260831 and 19299306

Much like the other motors we’ve talked about thus far, the LSX376 comes in two different versions; both of which utilize the LSX-Series iron block and are built with boost in mind. Neither of the versions come equipped with an intake manifold or accessories, providing owners the opportunity to tailor the motor to their specific needs.

  • LSX376-B8— This is the less stout version of the LSX376. Because of the iron block, the LSX376 is going to weigh 120-130 pounds more than an LS3 but will hold up to boost far better due to the intrinsic rigidity of its construction. The B8 is built with a boost-friendly 9.0:1 compression ratio and utilizes forged pistons. However, the connecting rods and crankshaft use standard powdered metal and nodular iron construction respectively. Chevrolet Performance recommends no more than 8 psi be thrown at it.
  • LSX376-B15— This version of the LSX376 is good for up to 15 psi according the Chevrolet Performance. This is due to its all-forged rotating assembly and, again, a conservative 9.0:1 compression ratio. The B15 also comes equipped with a higher-lift camshaft to take advantage of all that pressurized atmosphere.
LSX376Whipple

Featuring all-forged internals, the LSX376-B15 is ready to handle up to 15 psi right out of the box.

Both versions of the LSX376 use stock LS3 mounting locations for the motor mounts and accessories, making it a great choice if you are looking to upgrade the engine in your current late-model GM ride in preparation for boost.

“The LSX376 typically isn’t as popular because GM reports the output without the use of a power adder,” Was said. “When you’re comparing prices without factoring in the added 15 pounds of boost, it’s obviously not going to make sense.”

But those in the know might want to take a look at the LSX376 for its capability to produce much more than just the advertised numbers with the addition of a power adder.

Cost: $7,495 or $9,974

Lucky13

The 7.0-liter LS7 packs big-block power into a small-block package and is one of the reasons we selected it to motivate Project Lucky 13.

4. LS7

Chevrolet Performance— PN 19244098

The venerable LS7 is arguably one of the most popular motors in recent history. Offering big-block power in a small-block package, this rev-happy large bore motor is just as happy at the drag strip as it is on the road course. And, with the ability to run a dry-sump oiling system, you never have to worry about excessive g’s starving the engine of life-giving lubrication. Factor in the fact that the LS7 comes with a forged crank, lightweight titanium connecting rods and friction-coated aluminum pistons, and this crate engine is giving you a lot of bang — and durability — for your buck. It also comes with CNC-ported heads stuffed with 2.20-inch titanium intake valves and 1.610-inch sodium-filled exhaust valves. We love the LS7 around these parts so much that we selected it to motivate Lucky 13, our fifth-gen road-racing-focused Camaro.

Cost: $16,503

2012 “LSA” 6.2L V-8 SC

The LSA packs a 558-horse punch but is less robust than the LS9.

5. LSA/LS9

Chevrolet Performance— PN 19331507 and 19269165

Until recently, these two motors where the pinnacle of GM powerplants and are still amazing pieces of internal-combustion wizardry. While both are similar in design, there are some significant design differences to be aware of:

  • LSA— Much like the LS3, Chevrolet Performance offers the LSA in several formats such as the E-Rod and Connect & Cruise. The E-Rod again comes as a 50-state legal offering and includes exhaust manifolds, catalytic converters and ECU. The Connect & Cruise option arrives as if it had just been yanked out of a CTS-V or ZL1 and includes the transmission, wiring harness and ECM. The LSA comes with a wet-sump oiling system and features oil squirters for cooling the underside of the pistons. It is sporting a sixth-generation 1.9-liter TVS huffer stuffing a tame 9 psi through the 6.2-liter mill. It offers a forged steel crank with powdered metal connecting rods driving aluminum pistons. All together, the mill makes 558 horsepower.
LS9

The LS9 is straight out of the Corvette ZR1 and delivers world-beating performance.

  • LS9— The LS9 is basically a beefed-up, more potent version of the LSA. Featuring forged aluminum pistons, forged titanium connecting rods and a forged steel crankshaft, the bottom end is nearly bullet proof. It also features a dry-sump oiling system, ideal for extreme handling duties and also includes oil squirters for cooling the bottoms of the pistons to prevent hot spots and detonation under boost. Induction duties are handled by a 2.3-liter TVS supercharger putting out 10.5 psi breathing into high-flow heads stuffed with titanium valves on the intake and sodium filled valves on the exhaust. The LS9 also offers a substantially more aggressive camshaft that helps boost (pun intended) output to 638 horsepower. While the LS9 is a potent power producer, its quality is reflected in its price tag.

Cost: $14,006 and $25,509

LT1DirectInjection

The LT1 features variable valve timing, direct injection and Active Fuel Management making it one of the most technologically advanced motors GM has ever produced and is certainly the most advance pushrod motor of all time.

6. LT1

Chevrolet Performance— PN 19328728

You’ve probably heard all the hoopla about the all-new direct-injected LT1, which debuted in the C7 Corvette and can now be found under the hood of the sixth-gen Camaro as well. While it isn’t as big a leap forward as the gen III motor was in comparison to the original small-block Chevy, it is still a serious advance in technology. The LT1 features direct injection, variable valve timing and Active Fuel Management. The LT1 is also available in dry sump or wet sump configurations. The bottom end is much more robust than its LS progenitors and utilizes a forged steel crankshaft and forged powdered metal connecting rods. It also uses a substantially larger camshaft than the out going LS3 and ups the compression to 11.5:1.

The LS3 will probably continue to dominate the market until the aftermarket catches up as far as swap kits, engine mounts, exhaust and all that.- Greg Was, Pace Performance

If you’re looking to experiment with variable valve timing and direct injection, this is the perfect engine for you. And, due to its new features, the LT1 has a very flat horsepower and torque curve which means this motor pulls like a freight train all the way up to 6,600 rpm where it produces 460 horsepower. In addition, this brute makes more than 300 lb-ft of axle-twisting torque at just 1,000 rpm and keeps right on pulling to make a peak of 465 lb-ft at just 4,000 rpm! Stuffing one of these mills in your project is a great way to beat everyone to the punch because a lot more of these swaps are coming down the line.

However, the LT1 does require more creative problem solving when it comes to performing a swap on your favorite late-model or early-model GM car.

“The LS3 will probably continue to dominate the market until the aftermarket catches up as far as swap kits, engine mounts, exhaust and all that,” Was said. “We’re starting to get there with the serpentine kits, since you have to add power steering to the LT1 to be able to swap it in.”

Cost: $11,000

78LT4malibu(1) 2

The king of the hill, the LT4. Named after several other legendary motors, this beast puts out 650 ponies and is fine sitting in freeway traffic all day (although that’s not what it’s best at). This LT4 resides between the fenders of this ’78 Malibu from Midwest LSX.

7. LT4

Chevrolet Performance— PN 19332621

This is it! This is the king of the heap. The most powerful motor that the General has ever offered in a regular-production Chevrolet. The supercharger, an Eaton R1740 TVS, is slightly smaller than the LS9’s at 1.74 liters, but is substantially more efficient and sees speeds of up to 20,000 rpm. The smaller supercharger also ensures that it comes up to speed more quickly. The Rotocast A356T6 aluminum LT4 heads are stuffed with titanium valves and the cylinders house dished forged aluminum slugs to help lower its compression to 10:1, which is still relatively high considering the mill sees up to 9.5 psi. The bottom end is comprised of a forged steel crank that is stronger than the LT1’s and is spun by forged connecting rods. If you’ve got the coin, we are positive that you won’t be disappointed slipping an LT4 between the fenders of your beloved project.

“It’s hard to beat the LT4 as far as price goes,” Was said. “You get 650 horses for a pretty good deal.”

Cost: $15,625

Which one should you pick?

A lot of these engines have positives and negatives, especially when you consider what you are building the car to do. Some are high-revving lightweight earth movers that are better suited for autocross events and track days. Others are heavy-hitting supercharged fire breathers that may be more at home on the drag strip, or iron-block behemoths that are ready to handle a butt-load of boost. And while the final decision will come down to what your projects needs, you can’t really go wrong in selecting any one of these mills to motivate your ride.

Choosing may be the most difficult part of your next project.

Let us know in the comments below which one you would choose and, in case you missed it, check out our recent build of an LSX 376B15.

2014 "LT-1" 6.2L V-8 VVT DI (LT1) for Chevrolet Corvette

Article Sources

About the author

Chase Christensen

Chase Christensen hails from Salt Lake City, and grew up around high-performance GM vehicles. He took possession of his very first F-body— an ’86 Trans Am— at the age of 13 and has been wrenching ever since.
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