[26][27][28] Nicknamed the "Mighty Mouse," the Turbo-Fire soon became popular within the hot rodding community too, along with scoring wins in stock car racing.
The top-of-the-line model produced 283 hp (211 kW; 287 PS), giving it a 1:1 cubic inch to horsepower ratio;[18] this lowered the Corvette's 0–60 mph (0–97 km/h) to 7.2 seconds.
[27] General Motors would produce more powerful and larger displacement iterations of the small-block, until stringent emission regulations in the late 1960s severely limited performance.
Other modifications such as a better flowing intake manifold and cylinder heads gave the LT1 a power output of 300 hp (224 kW; 304 PS).
Another domestic rival, Chrysler Corporation, had stopped building passenger cars with V8 engines years prior, relegating them to its trucks and SUVs.
Stephens had the task of designing an engine that was not only more powerful than the previous small-block iterations, but one that could also deliver better fuel economy and meet emissions standards.
[35] Another advantage is that there are fewer mechanical components such as timing chains and extra camshafts, which increases reliability by keeping the engine simple.
[39] Other modifications include long runner intake manifolds, powder-forged connecting rods and the introduction of six-bolt main bearings (as opposed to four on the previous generations).
Powder-forging is also more cost-effective compared to traditional die forging, reducing the amount of tooling required to trim inconsistencies in hot-forged connecting rods.
The SSC Ultimate Aero TT also utilized the LS6 block, albeit with an enlarged displacement of 6.3 L (384.4 cu in) and the addition of two turbochargers.
Applications: The Vortec 5300 LM4 (VIN code "P") is an aluminum block version of the LM7, and had a short production life, as did the specific vehicles in which LM4s are found.
[56] The Vortec 6000 or new VortecMAX version is based on the Holden L76 engine, and features variable cam phasing, along with Active Fuel Management.
L77 engines were released in the Holden Commodore Series II VE range in both manual and automatic transmissions, along with the Chevrolet Caprice PPV (police car).
The LZ1 is almost entirely based on its predecessor, the LFA, but with some revisions, such as including up-integrated electronic throttle control, long-life spark plugs, GM's Oil Life System, Active Fuel Management, and variable valve timing.
The Vortec 4800 base engines were dropped from the Chevrolet Tahoe and GMC Yukon in favor of the 5300 with Active Fuel Management.
The Vortec 5300 LH6 (VIN code "M") with Active Fuel Management replaced the LM4 for 2005, and was the first of the Generation IV small-block V8 truck engines to go into production.
Though it has the same displacement as the Vortec 5300 LY5, it features an aluminum block instead of iron, and uses the same cylinder head casting as the Generation III LS6 engine.
The LS4 is adapted for transverse front-wheel drive applications, with a bellhousing bolt pattern that differs from the rear-wheel-drive blocks (so as to mate with the 4T65E).
As of early 2022, the LS7 is no longer being supplied as a crate engine, with Chevrolet intending to fulfill all current orders until inventory is depleted.
[74] This family was designed as a replacement for the LS2 but enlarged to better accommodate variable valve timing and Active Fuel Management while still generating decent performance.
Engines built prior to April 1, 2006, contained AFM hardware; however, the mode was not enabled in the PCM, and thus the system was not functional.
Engines built after this date also lacked any AFM hardware, and instead used a valley cover plate similar to the L20, until the debut of the L94 variants mentioned below.
The L99 is derived from the LS3 with reduced output but adds Active Fuel Management (formerly called Displacement on Demand) and variable valve timing, which allows it to run on only four cylinders during light load conditions.
[75] Note: GM previously used the LS9 RPO code on 1969 and later Chevrolet trucks (both 2WD and 4WD) including Blazers, Jimmys, and Suburbans, as well as car carriers.
The LT4 engine is based on the same Gen 5 small block foundation as the Corvette Stingray's LT1 6.2L naturally aspirated engine, incorporating several unique features designed to support its higher output and the greater cylinder pressures created by forced induction, including: Rotocast A356T6 aluminum cylinder heads that are stronger and handle heat better than conventional aluminum heads, lightweight titanium intake valves, forged powder metal steel connecting rods, 10.0:1 compression ratio, enhanced performance and efficiency enabled by direct injection, forged aluminum pistons with unique, stronger structure to ensure strength under high cylinder pressures, stainless steel exhaust manifolds for structure at higher temperatures, aluminum balancer for reduced mass, and standard dry-sump oiling system with a dual-pressure-control oil pump.
Rather than allow a "high-strung" small-block to fail the heavy-duty truck market, the iron block, lack of both stop-start and cylinder deactivation, longer stroke and rod ratio, lower compression, lesser 87 Octane requirement, greater displacement, forged connecting rods, and forged crankshaft with central counterweights all suggest that the L8T was designed specifically to assuage the heavy-duty truck market's concerns.
[86] Applications: General Motors announced in January 2023 that plans for a sixth generation of small-block were in place, with the company investing $854 million into its various manufacturing plants.
[87][88][89] The eighth character in the VIN or the RPO code from the glove box sticker can be used to identify which type of LS engine a vehicle has.
[109] Chevrolet Performance LSX Bowtie block includes LSX specific six-bolts-per-cylinder head bolt pattern, billet-steel six-bolt dowel-located main bearing caps, extra-thick deck for maximum clamping force, extra-thick cylinder walls allow increased bore capacity (maximum 4.2 in (106.7 mm) bore still allows 0.2 in (5.1 mm) minimum wall thickness), true priority main oiling system, main web bay-to-bay breathing holes reduce crank windage, orange powder coat finish, machined bore at 3.88 in (98.6 mm) is ready for final boring/honing.
In addition to the solid block, a waterjacketed version was designed to provide better cooling options for street or endurance purposes.