LS1: years, specs & known problems

By CarWhere Research · Updated November 3, 2026

The LS1 is the 5.7-liter all-aluminum V8 that launched GM's Gen III small-block family in the 1997 Corvette at 345 hp. It later made 350 hp in the 2001–2004 Corvette, 305–325 hp in the 1998–2002 Camaro Z28 and SS and Firebird, and 350 hp in the 2004 Pontiac GTO.

The LS1 debuted in the C5 Corvette for 1997 as the first Gen III small-block, an all-aluminum pushrod V8 that was lighter and stiffer than the cast-iron engines it replaced. It displaces 5,665 cc from a 99 mm bore and 92 mm stroke and uses electronic throttle control in the Corvette. It has no connection to the 1992–1997 Gen II LT1 beyond the 5.7-liter displacement.

From 1998 the LS1 also went into the Camaro Z28 and SS and the Pontiac Firebird Formula and Trans Am until those cars ended after 2002. For 2001 the Corvette version gained revised manifolds and rose to 350 hp, and the 2004 GTO carried it for its first year. The engine has no engine-specific NHTSA recall; the owner-reported issues are cold-start piston noise and oil use on some engines.

LS1 at a glance

GM 5.7L LS1 V8 (Gen III small-block): model years, fuel and peak GM-published output
Engine	Model years	Fuel	Peak hp	Peak torque (lb-ft)	Documented problems	Recalls
GM 5.7L LS1 V8 (Gen III small-block)	1997–2004	Gasoline	350	375	1	0

CarWhere lists 1 documented problem and 0 NHTSA recalls for the LS1, each with a source.

LS1 specifications

LS1: design facts (1997–2004)
Specification	Value
Displacement	5,665 cc (346 cu in)[2]
Bore × stroke	99.0 mm × 92.0 mm[2]
Block and heads	Cast aluminum block and cylinder heads[2]
Compression ratio	10.1:1[2]
Fuel system	Sequential port fuel injection[2]
Throttle	Electronic throttle control (Corvette)[1]
Engine family	First Gen III small-block, introduced in the 1997 Corvette[1]

LS1 horsepower and torque by year

LS1: GM-published horsepower (hp) and torque (lb-ft) by model year and application
Model years	Application	Horsepower (hp)	Torque (lb-ft)	Source
1997–2000	Corvette	345	350	[1]
2001–2004	Corvette, six-speed manual375 lb-ft at 4,400 rpm	350	375	[2]
2001–2004	Corvette, automatic360 lb-ft at 4,000 rpm	350	360	[2]
1998–2000	Camaro Z28	305	—	[3]
1998–2000	Camaro SS327 hp with optional SLP exhaust	320	—	[3]
2001–2002	Camaro Z28	310	340	[3]
2001–2002	Camaro SS	325	350	[3]
2004	Pontiac GTO	350	365	[4]

"—" means we could not confirm the figure from a primary source.

Which GM vehicles have the LS1?

GM models and model years offered with the LS1
Model	Model years	Notes
Chevrolet Corvette (C5)	1997–2004	Base engine; the 2001–2004 Z06 used the related LS6
Chevrolet Camaro Z28 and SS	1998–2002
Pontiac Firebird Formula and Trans Am	1998–2002
Pontiac GTO	2004	Six-speed manual or four-speed automatic

LS1 problems and what to check

Cold-start piston slap and oil consumption (1997–2004 (owner reports))

Minor

Owners report a knocking noise for the first minutes after a cold start that fades as the engine warms, commonly attributed to piston-to-bore clearance, and some engines use more oil than owners expect. Correcting the noise properly requires engine disassembly, so most owners live with it when compression and oil pressure are healthy.[5]

Symptoms

Light knock for the first few minutes after a cold start
Oil level dropping between changes
Blue smoke at startup on worn engines

Check before buying

Hear the car start from fully cold
Ask how much oil it uses between changes
Run a compression or leak-down test on high-mileage engines

Related GM research

Confirm a vehicle really has the LS1.

Engine and transmission RPO codes are recorded against the VIN. The CarWhere build sheet decodes a Chevrolet VIN into the factory-ordered option codes on record — engine, transmission, axle and packages. $9.99, instant.

Chevrolet build sheet by VIN

Frequently asked questions

How much horsepower does an LS1 have?

It depends on the car and year: 345 hp in the 1997–2000 Corvette, 350 hp in the 2001–2004 Corvette and 2004 GTO, 305–310 hp in the Camaro Z28 and 320–325 hp in the Camaro SS.

What cars came with the LS1?

The 1997–2004 Corvette, the 1998–2002 Camaro Z28 and SS, the 1998–2002 Pontiac Firebird Formula and Trans Am, and the 2004 Pontiac GTO.

Is the LS1 the same as the LT1?

No. The 1992–1997 LT1 is a Gen II small-block with iron-block roots, while the LS1 is the all-aluminum Gen III design that replaced it; the current 6.2L LT1 is a separate Gen V engine.

What displacement is the LS1?

The LS1 displaces 5,665 cc, or 346 cubic inches, from a 99 mm bore and 92 mm stroke.

Was the LS1 ever recalled?

No NHTSA safety recall covers the LS1 engine itself. Check each car's VIN for open recalls on other components.

Sources

Ratings are GM-published figures as cited; descriptions are CarWhere’s own summaries of the sources below. Repair costs appear only where a source states them and vary by shop and region.

GM Press Release: January 6, 1997, NAIAS — Corvette — Corvette Action Center (GM release archive)
2001 Corvette Specifications — CorvSport
History of Chevrolet Camaro Engines: 4th Gen Brings Big Power (Feb. 2015) — Torque News
2004 Pontiac GTO: What's New — Cars.com
Piston Slap: To lift, slap, or ignore the LS1? — Hagerty (secondary reference)

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Independent reference compiled by CarWhere — not affiliated with or endorsed by General Motors. Chevrolet, GMC, Cadillac, Corvette, Duramax, Vortec and the model names are trademarks of their owner.