Inside Chevy’s Gen III Small-Block

The ’02 Vette LS6 engine...        read full caption The ’02 Vette LS6 engine is SAE-net-rated at 405 hp @ 6,000 rpm, and 400 lb-ft of torque at 4,800 rpm.

The pace of LS1 technology...        read full caption The pace of LS1 technology has evolved quickly since the engine’s introduction in ’97 Corvettes. Stock fourth-gen F-bodies run low 13s, but with some serious tweaking, the School of Automotive Machinists’ ’99 SS Camaro has broken the 9-second barrier naturally aspirated.

For 2002, new Corvettes use a 10.5:1 LS6 engine that makes 405 net horsepower on today’s pump gas. And that’s real power as installed in the vehicle, not phony musclecar horsepower. It does this while meeting all of today’s stringent emissions and fuel economy standards. The Vette’s 345ci engine is not your father’s LS6 big-block, but it’s not a conventional small-block, either. The LS6 is the newest member of Chevy’s Gen III small-block family, a ground-breaking, high-tech pushrod engine that—except for the connecting rod bearings—shares no parts with any classic Chevy small-block.

Gen III small-blocks debuted as the LS1 in ’97 Vettes. As of 2002, only fullsize vans retain conventional small-blocks, but even that era is coming to an end. The high-tech mill is rapidly gaining favor in numerous racing venues where fuel-injected engines are allowed to compete. Takeouts are appearing in salvage yards, and GM as well as aftermarket performance parts are beginning to fill up the pipeline. With help from leading Gen III pioneers including General Motors Performance Parts (GMPP), Hank the Crank (HTC), The School of Automotive Machinists (SAM), TTS, Westech Automotive, and other sources let’s take a look at what makes this engine run.