Chevy 350 enginePhoto: Mr.choppers · CC BY-SA 3.0

Chevrolet · Small-Block Chevrolet

Chevy 350

The small-block that became an industry standard

350

Cubic inches

Few American engines have matched the 350's combination of production volume, affordability, parts support and adaptability. It became the default small-block for generations of street, race and swap builds.

Key variants

All variantsEarly performance 350Emissions-era 350L98 / later EFI 350

Displacement

350 ci

Bore

Stroke

3.48"

Years

1967–2002 in major production applications

Key Takeaway

The 350 paired a 4.00-inch bore with a 3.48-inch stroke and became the most broadly produced and supported member of the traditional Chevrolet small-block family.

Technical Specifications

Compression: Varied widely across decades and applications
Horsepower: Varied widely from emissions-era versions to high-output performance applications
Torque: Varied widely by application
Architecture: 90° OHV V8 · Gen I Chevrolet small-block
Block: Cast iron
Cylinder heads: Cast iron in most factory versions; aluminum heads common in aftermarket builds
Valvetrain: Pushrod OHV · 2 valves per cylinder
Aspiration: Naturally aspirated in standard production form
Fuel delivery: Carbureted, throttle-body injection and port fuel injection depending on year/application
Firing order: 1-8-4-3-6-5-7-2
Main bearings: 5

The 350 paired a 4.00-inch bore with a 3.48-inch stroke and became the most broadly produced and supported member of the traditional Chevrolet small-block family.

Internal Specifications

Variant-specific values are labeled. Engine families that span multiple years or RPOs can have different heads, cams, induction and rotating parts, so the exact code/year always takes priority.

Identification & Output

Engine codes / RPO: LT-1, L98
Casting numbers: 186 / 492 / 414-family high-performance LT-1 head references varied by production date and service replacement
Power rating: SAE gross on early engines; SAE net from the 1972 model year onward
Horsepower RPM: 370 hp @ 6000 rpm (1970 Corvette LT-1 reference); other 350 versions varied widely
Torque RPM: 380 lb-ft @ 4000 rpm (1970 Corvette LT-1 reference)

Rotating Assembly

Crankshaft: Forged steel crankshaft in 1970 LT-1 high-performance applications; other 350s varied
Connecting rods: Forged steel connecting rods in 1970 LT-1 high-performance applications
Rod length: 5.70 in
Pistons: Forged aluminum high-compression pistons in LT-1 applications; production 350 piston design varied by version
Piston pin: 0.927 in nominal small-block pin diameter
Rear main seal: 2-piece on early engines; 1-piece on later production
Deck height: 9.025 in nominal Gen I small-block deck height
Main journal: 2.45 in
Rod journal: 2.10 in

Cylinder Heads

Chamber: Approx. 62–64 cc in LT-1 high-performance head combinations; production 350 chambers varied widely
Intake valve: 2.02 in (1970 LT-1)
Exhaust valve: 1.60 in (1970 LT-1)

Cam & Valvetrain

Camshaft: 1970 LT-1: GM 3972178 mechanical flat-tappet cam
Cam lift: Approx. 0.459 / 0.485 in intake/exhaust with 1.5:1 rockers (LT-1 reference)
Duration @ .050: 242° / 254° intake/exhaust (LT-1 reference)
LSA: 116° LSA (LT-1 reference)
Rocker ratio: 1.50:1

Operating Specs

Redline / max RPM: 6500 rpm factory tach redline in 1970 Corvette LT-1 applications
Fuel / octane: 1970 LT-1's 11.0:1 factory calibration was intended for period high-octane premium fuel; modern pump-fuel needs depend on timing, compression and tune
Oil capacity: 1970 Corvette LT-1: 4 qt crankcase refill plus filter capacity; approximately 5 qt total with filter in factory service specifications
Induction: 1970 LT-1: 780-cfm Holley four-barrel on aluminum dual-plane/high-rise intake; Rochester carburetion, TBI and TPI were used on other 350 variants
Ignition: Cam-driven distributor; transistorized ignition used on some performance applications
Oil pan / sump: Baffled high-performance oil pan in LT-1 applications
Production notes: The 350 spans carbureted, TBI and tuned-port EFI eras, so builder specs must be tied to the exact RPO/year. The advanced specs on this page use the 1970 LT-1 as the performance reference; 1,287 Corvettes were built with RPO LT1 in 1970.

Service Specs

Spark plug: AC R43 reference for 1970 Corvette LT-1
Spark-plug gap: 0.035 in (1970 Corvette LT-1 reference)
Ignition timing: 8° BTDC initial timing reference for 1970 Corvette LT-1
Valve lash: 0.024 in intake / 0.030 in exhaust hot for the factory 3972178 LT-1 mechanical cam
Oil pressure: Approx. 35–45 psi normal operating reference in period Corvette specifications

Compatibility Notes

Block, crank, rear-main-seal and valvetrain details vary substantially across the 350's long production run.
Later one-piece-seal engines require the matching crank/flywheel or flexplate combination; do not assume early and late rotating parts interchange directly.

Notable Applications

CamaroCorvetteChevelleNovaFull-size Chevrolet modelsChevrolet and GMC trucksNumerous GM vehicles

Strengths

Enormous aftermarket
Excellent parts availability
Strong balance of torque and rpm
Easy to build at many power levels

Weaknesses / Watch-outs

Factory castings and components vary greatly by year
Many low-performance versions require substantial upgrades for serious power

Common Upgrades

Aluminum cylinder heads
Hydraulic roller cam conversion or performance cam
Intake and carburetor or EFI
Headers

Racing History & Legacy

The 350 has competed in virtually every form of American grassroots motorsport and became a standard building block for circle-track, drag, marine and street performance.

Arguably the most recognizable Chevrolet small-block displacement and one of the most supported V8s ever built.

References & Image Credit

Engine image: Mr.choppers · CC BY-SA 3.0 · source

GM Heritage Archive vehicle information kits

manufacturer archive

1970 Chevrolet Corvette vehicle information kit — LT-1 factory specifications

manufacturer specification

Wikimedia Commons Chevrolet 350 engine image

licensed media

1970 Corvette LT-1 operating and tune-up specifications

historical specification

ChevelleWorld GM camshaft service-number reference

specialist reference

Corvette Action Center — 1970 LT-1 Corvette production

historical specification

Key Factory / Build Variants

Early performance 350

Late 1960s–early 1970s

Multiple high-output gross-horsepower versions

Established the 350 as Chevrolet's mainstream performance small-block.

Emissions-era 350

1970s–1980s

Application-dependent net ratings

Kept the small-block in mass production through a difficult performance era.

L98 / later EFI 350

1980s–1990s

Higher-output tuned-port and EFI combinations

Returned the 350 to a stronger performance identity before the LS era.

Engineering Notes Worth Knowing

Block, head, rear-main-seal and valvetrain details vary significantly by production year.

The 4.00-inch bore and huge aftermarket make cylinder-head and camshaft choices almost endless.

Hydraulic roller production blocks from later years are especially popular for street-performance builds.

History · context · related reading

The Story Behind Chevy 350

The 350 became more than an engine size; it became the default language of American hot-rodding. Its production volume, parts interchange and broad aftermarket made it equally at home in daily drivers, circle-track cars, drag cars, boats and swaps.

Industry standard

How the 350 became the default Chevy V8

Why production volume, parts availability and an enormous aftermarket turned one displacement into a universal hot-rodding reference.

Survival story

From muscle era to emissions era and back

How the same basic 350 architecture moved through changing compression ratios, emissions systems, carburetion and EFI.

Aftermarket

Why almost every kind of 350 build already has a recipe

The decades of racing and street development that made proven combinations easy to copy at nearly every power level.

TorqueList Garage Reference Series

See this engine inside the full Chevrolet reference catalog.

The same Engine Library data now powers a more detailed mobile-friendly catalog with technical specs, variants, engineering notes, history and related stories.