LS1 Engine Guide: Specs, Features, & More

1997-2004 Chevrolet LS6 Engine Ultimate Guide

When people talk about V8’s, especially in the domestic world, the LS series of engines always come to mind. These are relatively inexpensive and robust platforms to build excellent street/strip engines from.

In this article, we’ll be walking through the history of the LS1, some general technical specifications as well as provide some further insight into notable vehicles and/or records that the LS1 has been able to collect over the years.

A Brief History of The LS1:

The LS1 is the spiritual successor to the “small block V8” that GM uses in rear-wheel-drive cars, trucks, and vans. It was introduced in 1995 as the “GEN III” engine and it only shared rod bearings, lifters, and bore spacing with its predecessors (which was in production 1955 until 2003).

Little did GM expect for the LS1 has become a legend in its own time, offering impressive “out of the box” performance for the physically compact package. For those lucky enough to have the LS1 in their cars, the blocks were made of aluminum, while the truck and van versions were cast iron.

Even the aluminum blocks for this generation of motor offered nearly the same strength as the older Gen I/Gen II iron blocks. Further advancements compared to previous generation small block V8’s was the change from distributor ignition to coil-near-plug design, offering much more precise ignition timing using computers.

The development of the LS1 was mainly attributed to the ever-increasing CAFE (The Corporate Average Fuel Economy) requirements, thus reducing weight, increasing power, and improving fuel efficiency were the problems that the LS1 was designed to solve for GM.

LS1 Horsepower, Torque & Technical Specifications (aka the “Geeky Stuff”)

Illustration by David Kimble

Other than the displacement (5.7L / 347.5ci), the aforementioned rod bearings and physical dimensions with previous generation LT1 small block, the LS1 was a new all-aluminum single-cam pushrod engine with a bore and stroke of 99 mm × 92 mm (3.898 in × 3.622 in) making this GM’s first all-aluminum production V8.

With the advancement of materials over the previous generation small-blocks, the LS1 offered a 45hp bump in power as well as a 12% reduction in weight compared to the outgoing LT1 engine used in the C4 Corvette.

The LS was originally intended and designed as an alloy block. To add strength, engineers created a deep skirt block where the pan rail extends below the bottom of the 4-bolt main caps using a pair of 8mm horizontal bolts to laterally locate each main cap. Other major changes included:

• A larger 55mm (2.165-inch) journal hydraulic roller camshaft
• Unique, cathedral-shaped intake port heads
• Hypereutectic aluminum flat-top pistons providing a 10.2 compression ratio
• Nodular iron crank
• 154.7mm (6.089-inch) powdered metal rods.

Topping off the engine is a thermoplastic composite intake manifold intended to reduce weight and lower inlet air temperatures.

Furthermore, with the removal of the distributor, the ignition is now controlled by the ECU, firing a set of eight coils mounted near the spark plugs. The LS1 also changed the firing order to 1-8-7-2-6-5-4-3 which is aligned with more modern V8’s.

When the LS1 was introduced in the C5 Corvette, it was rated at 345 hp (257 kW) at 5,600 rpm and 350 lb-ft (475 Nm) at 4,400 rpm. After further improvements to the intake and exhaust manifolds in 2001, the rating increased to 350 hp (261 kW) and 365 lb-ft (495 Nm). The LS1 was used in the Corvette from 97-04, ‘98-’02 Camaro/Firebird as well as the ‘04 Pontiac GTO/Holden Monaro.

The C5 Z06 utilized a tweaked version of the LS1 which was known as the LS6, which produced 405 bhp (302 kW) and 400 lb-ft (542 Nm) of torque. The LS6 shares its basic block architecture with the LS1 engine, but other changes were made to the design, such as:

• Windows cast into the block between cylinders
• Improved main web strength,
• Bay to bay breathing
• An intake manifold and MAF-sensor with higher flow
• A higher lift and increased duration camshaft
• A bump of compression ratio to 10.5:1, sodium-filled valves
• A revised oiling system better suited to high lateral acceleration.

There were four main displacements of LS engines, 4,806 cc (293.3 cu in), 5,327 cc (325.1 cu in), 5,665 cc (345.7 cu in), 5,967 cc (364.1 cu in). With cylinder bore size between 96 mm (3.78 in), 99 mm (3.9 in), 101.6 mm (4.00 in) and rod strokes of 83 mm (3.27 in) and 92 mm (3.62 in). The 4.8L, 5.3L and 6.0L motors were generally iron block and used in trucks and vans.

Although there are many “pros” for the LS1 engine, there are some common issues with the engine and are further exacerbated in motorsport environments. The first common issue with the LS1 is oil windage issues resulting in oil starvation and a list of trickle down issues to hydraulic lifters followed by camshaft bearings, valve springs, rocker bearings, and timing chain tensioners (in the earlier versions of the LS1).

The one thing that GM did correctly right out of the gate was the design of the cylinder heads on the LS1 engine- they were easily the best flowing and least costly option available to hot rodders; it took the aftermarket well over 5 years to develop something as high-flowing as the stock LS1 heads.

Notable Vehicles Using the LS Engine

Since the LS based engines have a compact package and known for making reliable power, many small brand manufacturers have adopted this GM motor in some very interesting vehicles.

Probably the most recognizable vehicle to use an LS based motor is the Hennessey Venom GT, with a pair of twin turbos on the 427ci LSX motor, it produces north of 1200hp and holds the Guinness World Record for fastest accelerating production car ever, sprinting to 200 mph in 14.51 seconds.

Adding to the list of niche brand manufactures using an LS based motor as the beating heart would be SSC Ultimate Aero TT, which prior to the arrival of the Bugatti Veyron and Hennessey Venom GT held the title of the fastest production vehicle from 2007 until 2013 clocking 256.14 mph with a theoretical top speed of 273 mph.

Thrown into the mix is Zenvo, a Danish supermarket maker who’s ST1 uses a 7.0L twin-charged (turbo and supercharged) engine modeled after the LS7 but made of CNC billet aluminum produces 1104hp and 1050 lb-ft torque.

Drifters have also embraced the LS engines as the “swap of choice” making cheap reliable power in Nissan’s S13/14/15 as well as the Z33, RX-7 FC & FD along with the RX-8 chassis, BMW E36 & E46 chassis and even Porsche 911’s specifically the 996 chassis.

Chevrolet LS1 Specifications

Overview
Manufacturer	General Motors
Also called	GEN III (Vortec for the iron block truck/van applications)
Production	1996-2007

Layout
Configuration	90° V8
Displacement	4,806 cc (293.3 cu in) 5,327 cc (325.1 cu in) 5,665 cc (345.7 cu in) 5,967 cc (364.1 cu in)
Cylinder bore	96 mm (3.78 in) 99 mm (3.9 in) 101.6 mm (4.00 in)
Piston stroke	83 mm (3.27 in) 92 mm (3.62 in)
Block material	Aluminum Cast iron
Head material	Aluminum Cast iron
Valvetrain	OHV 2 valves per cylinder

Combustion
Fuel system	Sequential multi-port fuel injection
Fuel type	Gasoline, E85
Oil system	Wet sump
Cooling system

 

Horsepower & Torque
Horsepower	1997 – 2000: 345hp @ 5,600 rpm (257kW) 2001 – 2007: 350hp @ 5,600 rpm (261kW)
Torque	1997 – 2000: 350 lb-ft @ 4,400 rpm (475 N⋅m) 2001 – 2007: 365 lb-ft @ 4,400 rpm (495 N⋅m)