Performance Chevy LS Engine Comparison - LS Motors Decoded

The Ultimate Guide To Every Gen III And IV Small-Block Ever Built

Stephen Kim Dec 1, 2009 0 Comment(s)

Used primarily in light-duty trucks, the L76 is essentially an aluminum block variant of the LY6. Major differences include a higher compression ratio and a slightly larger cam, which boosts output to 366 hp and 376 lb-ft. Like the LY6, the L76 utilizes variable valve timing, but ups the ante even further with active cylinder deactivation. Interestingly, the L76 also powers the Pontiac G8 GT. The car version of the L76 drops variable valve timing and features an LS3 intake manifold, which sacrifices some hp while picking up some torque.

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Vortech 4800
The smallest of the Gen III/IV platform is also the least desirable. While they're very capable mills for their intended application and can power stock Silverados to respectable 14-second e.t.'s, their lack of cubes make them unlikely candidates for engine swaps. This assessment is only reinforced by the fact that they're just as expensive as the 5.3L at the wrecking yard. The Gen III LR4 was built from '99-06 for fullsize trucks and SUVs, and was replaced in '07 by the Gen IV LY2. Other than tweaks universal to all Gen IV motors, the difference between Gen III and Gen IV 4.8L small-blocks are negligible.

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