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The LS1 engine by General Motors was the beginning of the Gen III engine platform of V8 small blocks. This engine had a displacement of 5.7 L, similar to the Gen II models it replaced, but the block architecture changed significantly.
The design was changed to the point that the aluminum block LS1 was close in strength to the cast iron versions of its predecessor.
The LS1 was first introduced in the C5 Corvette in 1997, then followed with availability in the Chevrolet Camaro and Pontiac Trans Am and Firebird in 1998. 1999 saw the introduction of the LS1 in Australia, as a number of Holden vehicles started to offer this engine.
The Small Block Revolution
Overall, the LS1 was in production from 1997 until 2005. There were several features of the LS1 that made it unique and began to revolutionize the small block engine. In addition to the enhanced block strength, there are several other unique features introduced with the LS1.
The so-called “Cathedral Port” cylinder heads were first introduced on the LS1. This name was given based on the shape on the intake port area. Another major enhancement to its predecessor was replacing distributor ignition system with a coil near plug ignition system.
While the LS1 is no longer in normal production, there are many car enthusiasts who continue to use the LS1, or some variation thereof, to build a strong engine with great performance. One feature that makes all LS engines popular for project cars is the interchangeability of the different parts.
It is very likely that if you see someone rebuilding an LS engine, it is at least partially a LS1.
LS1 Performance Specs
The horsepower rating for LS1 varied greatly depending on the specific car model that the engine came in. In the Corvette offering, the LS1 was introduced in 1997 with 345 horsepower at 5600 RPM and 350 lb-ft at 4400 RPM. In 2001 the power and torque were increased slightly to 350 horsepower at 6000 RPM and 360 lb-ft of torque at 4000 RPM.
The LS1 engine is 5.7 L, or more precisely 346 cubic inches. This is only slightly smaller than its predecessor which came in at 350 cubic inches, which was also rounded off to 5.7L. The LS1 was designed with a bore of 3.90 inches and a stroke of 3.62 inches. This bore of 3.90 inches is smaller when compared to many of the later Gen III and IV engines, and reduced the head compatibility for this engine.
Head and Block Construction
The LS1 engine is constructed using aluminum block and cylinder head. As mentioned previously, the new block design offered great strength despite its aluminum construction. Designers can use the most exotic materials and likely gain improvements, although at great cost, but it is important to have the most robust design possible to take full advantage of the materials being selected.
The LS1 uses a conventional pushrod overhead valve (OHV) valve train. The valve architecture uses 2 valves, 1 intake and 1 exhaust per cylinder.
The LS1 engine was truly a big step for the small block V8 engine. Improved block strength and elimination of the distributor ignition system were just two of the major changes introduced with this engine. Many backyard mechanics are still building these engines and using them to show off this powerful engine in their project car of choice.