#1 — General Motors LS Small Block

In the mid 1990s, some sensed that the traditional, pushrod-style American V8 had reached its performance limits. And then, like its Gen. I small block forefather, the GM LS engine came along to spark a hot rodding revolution.

Compact, lightweight, and powerful, the original LS1 debuted in 1997 and produced 345 horsepower in the Chevrolet Corvette. The engine used much of Ed Cole’s original formula for the small block Chevy engine’s success — 90-degree configuration, 4.4-inch bore spacing, and a single-cam pushrod valvetrain — but added a few twists. All-aluminum construction on performance models made it lighter in weight; a smaller bore/longer stroke design made it more compact. And of course, modern fuel injection made the LS more efficient than the original Gen I. small block.

The LS engine family (Gen. III and Gen. IV) shared one other important characteristic with the original small block: versatility. The design of the LS platform allowed engineers to create different displacements off of the same basic foundation. Over the lifespan of the LS engine family, engines would be available in sizes varying from LS1’s original 346 cubic inches to the 427-cubic-inch LS7 — the largest small block ever!

The LS7 debuted in 2005 and ushered in the Gen. IV small block. The Gen. IV LS shared the same basic architecture as the early LS engines; however, it added new technology such as displacement on demand and variable valve technology. The Gen. IV lineage includes such legendary engines as the LS7, LS3, and LS9 — the supercharged 6.2L V8 that produced 638 horsepower for the Corvette ZR1!

So let’s summarize the credentials for the General Motors LS small block:

• Historical significance: Based off the legendary Chevrolet small block, the GM LS engine family helped re-ignite the hot rodding scene in the mid 1990s. LS engines have been used in Camaros, Firebirds, GTOs, and Corvettes, including some of the most potent Corvettes ever to hit the streets.
• Performance potential: Sure, the LS9 gave us 638 horsepower from the factory! But the entire LS lineage is loaded with performance potential thanks to a proliferation of aftermarket parts and the interchangeability of parts between the different LS engines. It’s one of the most hot-rodded engines in American performance history, and its light weight and compact design make it one of the most swapped, too. Nowadays, you can even find LS engines in 1930s and ’40s street rods and trucks.
• Versatility: From supercharged performance engines to durable truck engines, the LS engine family has something for everyone. In addition to the Camaros and Corvettes of the world, you can find an LS inside a Cadillac Escalade, Chevy Silverado, GMCs, Holdens, and more. The LS platform has proven suitable for about anything!
• Affordability: The amount of engines produced has made the LS attainable and affordable and the still-increasing availability of aftermarket parts has helped make it practical to work on. What’s more, LS engines are considered fairly easy to wrench on by veteran enthusiasts.

Best LS Engines

Although the GM LS engine family headlines our list of the top American performance engines of the last 30 years, we feel compelled to rank them individually. Here’s our best of the best:

1. LS9/LSA: Made for the 2009-2013 Corvette ZR1, the LS9 is a supercharged 6.2L engine rated at 638 horsepower — the most powerful of all small blocks. The LSA is a detuned version of the LS9 used for the Cadillac CTS-V and Camaro ZL1.
2. LS1:  This is the one that started it all! First offered for 1997, this engine featured a smaller bore and longer stroke than the previous two generations of small blocks and made 345 horsepower in the Corvette. More importantly, it laid the groundwork for the rest of the LS family and is one of the most swapped performance engines ever.
3. LS7: Introduced in 2005, the LS7 sported 427 cubic inches, making it the largest small block ever. It featured the same basis 4.4-inch bore spacing, the LS7 took advantage of new technologies in valve timing to produce 505 horsepower
4. LS3: Combine an updated version of the LS2 casting (larger bores) with higher-flowing heads, more aggressive camshaft, and revised valvetrain, and you essentially have the LS3. Introduced in 2008 for the Corvette, it delivered 430 horsepower in initial form and has been used in everything from the 2010-up Camaro SS to the Chevrolet SS.
5. LS6: Following on the heels of the LS1, the LS6 used better-breathing heads, cam, and intake to take things to another level for the Corvette Z06. It delivered 405 horsepower at its peak.

Top GM LS Modifications

• Exhaust Systems
• Headers
• Air Intake Kits
• Camshafts
• Pistons
• Cylinder Heads
• Harmonic Balancers
• Rocker Arms
• Engine Kits and Rotating Assemblies
• Intake Manifolds
• Engine Management Systems