SCORE Journal - The Official Publication of SCORE Off-Road Racing
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will cause the valve-to-block interference. The larger, 4.00-inch bore of the LS2 enables it to use LS1/LS6 heads, as well as L92- style heads (including LS3, LS9 and LSA engines). The 6.2L engines (LS3, L92, etc.) can use any head except for the LS7, while the 7.0L LS7 can use any LS-series head. BUILDING A POWERFUL AND DURABLE LS ENGINE Although some racing engine builders use iron cylinder blocks as the foundation for their engines, just about every one used in today's race vehicles use a lightweight aluminum block – and many start off as one of Chevrolet Performance's LS3 6.2L crate engines. "Most of the Unlimited class vehicles weigh in at 4,000 pounds or more," says Enger. "You really want the lightest possible engine package, so we build them with an aluminum block." That comparatively heavy curb weight also dictates the type of racing engine Turn Key Powertrain builds. "Our 419-cubic-inch stroker engine is a popular choice, because the additional stroke helps build the low-end torque that's necessary to get the vehicle moving a lower speeds, while still delivering the high-rpm horsepower that translates into high speed out on the course," says Enger. For those who are unfamiliar with the term, "stroker" engine is one that has a longer crankshaft stroke than the stock specification. It's an attribute that increases the displacement of the engine and expands its performance range, particularly when it comes to producing torque – the pulling power of an engine. For LS ENGINE REFERENCE GUIDE LS1/LS6 (5.7L / 346 cu in) – Produced between the 1997 and 2004 model years in the United States and stretching into 2005 in other markets. The high-outpt LS6 was introduced in 2001 in the Corvette Z06 and was manufactured through 2005. LS2/L76/L77 (6.0L / 364 cu in) – In 2005, the LS2 and the Gen IV design changes debuted, with L76 and L77 versions following. This engine is one of the most adaptable in the LS family, as LS1, LS6, LS3 and L92/L94 cylinder heads work well on it. LS3/L99 (6.2L / 376 cu in) – Introduced on the 2008 Corvette, the LS3 debuted with larger bores to increase displacement. The L99 version was equipped with GM's cylinder deactivation system as standard equipment on Camaro SS models with an automatic transmission. LS4 (5.3L / 327 cu. in.) – The most unique application of the LS engine in a car, the LS4 was a 5.3L version used in the front- wheel-drive Chevrolet Impala SS and Pontiac Grand Prix GXP. It has an aluminum block and unique, low-profile features, including a "flattened" water pump, to accommodate the transverse mounting position. LS7 (7.0L / 427) – The largest LS engine oªered in a production vehicle. Unlike LS1/LS6, LS2 and LS3 engines, it uses a Siamese- bore cylinder block design for its big, 4.125-inch bores. Competition-proven heads and lightweight components, such as titanium rods and intake valves, make the LS7 a street-tuned racing engine. LS9 (6.2L / 376 cu in) – The supercharged engine from the C6 Corvette ZR1, it was rated at 638 horsepower and used a strengthened 6.2L block, stronger heads and an Eaton TVS supercharger. LSA (6.2L / 376 cu in) – Another supercharged LS, this one was used in the Cadillac CTS-V and Camaro ZL1. Although similar to the LS9 in design, it is built with several diªerences, including hypereutectic pistons vs. the LS9's forged pistons and a smaller supercharger. Gen III & Gen IV truck engines – Although performance car engines typically carried "LS" designations, truck versions were generally labeled Vortec and were oªered in 4.8L, 5.3L, 6.0L and 6.2L displacements. The 4.8L was made exclusively with an iron block and the 6.2L was made only with an aluminum block. The 5.3L and 6.0L versions were manufactured with iron and aluminum blocks. 057 SCORE JOURNAL