LS1 & LS3 Differences

by Sameca Pandova
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The LS1 and LS3 are pushrod V-8 engines produced by General Motors. The LS1 was the first engine of the Generation III family and was later supplanted by the Generation IV family, which included the LS3. Both engines are compact, large displacement pushrod designs and well regarded for performance and durability.


The LS1, introduced in 1997, was the first of the Generation III engines, phasing out the Generation II LT1 engine in the General Motors lineup. An all-aluminum block, the LS1 was first offered in the Corvette but later in the Camaro and Firebird. The engine remained a performance product not offered in any trucks or sedans.


The LS3 is part of the Generation IV engines and replaced the LS2 in the Corvette for the 2008 model year. The LS3, while based on the Generation III family, is part of the Generation IV family, which incorporates displacement on demand and variable timing. The revised block of the LS3 features a larger bore compared with the LS1's, which allows displacement to increase from 5.7 to 6.0 liters.

Similarities in Design

The Generation IV engines are an evolution of the Generation III engines, and thus share many design features including a six-bolt main cap, four-bolt per cylinder-head bolt pattern and center main thrust bearing. Both families of engine also use distributor-less coil-on-plug ignition.

Differences in Design

The major differences between the LS3 over the LS1 include the increase in displacement due to the larger bore, greatly improved engine head design, a revised camshaft, a revised intake manifold and larger fuel injectors. The revised heads, which use rectangular ports similar to those on LS7 heads, are the main improvement, as the supporting modifications support the increased airflow. It should be noted that these heads are included on the 6.2-liter L92 and have been released by General Motors as separately purchasable upgrade parts.

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