The Chevrolet 350 is a V8 engine that powered millions of vehicles from 1967 onward

The Chevrolet 350 small block is a 5.7-liter V8 engine that General Motors produced for over four decades. It first appeared in 1967 and remained in production through 2002, making it one of the longest-running engine designs in automotive history. The 350 became the standard V8 for Chevrolet cars, trucks, and performance vehicles, and it remains common in used vehicles and restoration projects today.

The engine earned its reputation for reliability, affordability, and tunability. Factory horsepower ranged from around 250 hp in base versions to over 370 hp in high-performance variants, depending on the year and process. Because so many were built and so many survive, parts remain inexpensive and widely available.

Key Takeaways

  • The 350 small block displaces 5.7 liters and produces between 250 and 370 horsepower depending on the year and tune, with most versions landing in the 300–350 hp range.
  • The engine uses a cast-iron block and heads, weighs roughly 575 pounds dry, and fits in engine bays designed for earlier small blocks because Chevrolet maintained the same basic dimensions across generations.
  • Common problems include intake manifold gasket leaks, oil pan gasket failures, and carbon buildup in the combustion chamber, all of which are manageable with routine maintenance.
  • Rebuilding or modifying a 350 costs less than most V8 engines because parts are abundant and labor rates are competitive; a basic rebuild runs $1,500 to $3,000 in labor alone.
  • The 350 pairs with multiple transmission options including the Turbo 350 automatic, Turbo 400 automatic, and various manual boxes, so verify which transmission your vehicle has before sourcing parts.

Engine displacement, bore, and stroke specifications

The 350 small block has a bore of 4.00 inches and a stroke of 3.48 inches, which yields 5.7 liters (350 cubic inches) of displacement. This combination made the engine compact enough to fit in mid-size cars while producing enough torque for trucks and performance applications. The bore and stroke remained consistent across most production years, which is why parts interchange so readily.

The engine block is cast iron, as are the cylinder heads. The crankshaft is forged steel in most versions. Compression ratios varied by year and process, ranging from 8.5:1 in economy versions to 10.25:1 or higher in performance models. Higher compression ratios require higher-octane fuel and produce more power, but they also make the engine more sensitive to detonation and heat.

Horsepower and torque output across production years

Factory horsepower figures changed significantly over the 350's 35-year production run, largely due to emissions regulations and fuel quality changes. In 1967, the first 350s produced 300 hp. By the mid-1970s, tightening emissions standards dropped output to around 160–180 hp in some applications. The 1980s and 1990s saw a gradual recovery as engine management technology improved, with most late-model 350s producing 250–310 hp.

Torque output typically ranged from 380 to 410 lb-ft in stock form, though high-performance variants could exceed 420 lb-ft. The engine's torque curve was relatively flat across the RPM range, making it responsive from idle to redline. This characteristic made the 350 popular in both street cars and towing applications.

Common wear points and maintenance issues

The 350 small block is durable, but certain components fail more often than others. Intake manifold gaskets are the most frequent culprit—they develop leaks that allow coolant to seep into the oil, creating a milky sludge on the dipstick. This usually happens between 80,000 and 150,000 miles. Oil pan gaskets also fail regularly, causing slow drips that accumulate over time. Both repairs are straightforward but labor-intensive because the gaskets sit deep in the engine bay.

Carbon buildup in the combustion chamber increases over time, especially in engines running lower-octane fuel or with inconsistent oil changes. This buildup reduces compression and can cause pinging under load. Valve cover gaskets dry out and crack, allowing oil to seep onto the exhaust manifolds. None of these issues are catastrophic, but they require attention to prevent secondary damage like overheating or oil starvation.

The cooling system deserves attention in older 350s. The water pump typically lasts 60,000 to 100,000 miles before the bearing wears and the seal fails. Thermostats can stick, causing overheating or running too cold. Radiators accumulate sediment over decades and lose cooling efficiency. Regular coolant flushes and temperature monitoring prevent most cooling-related failures.

Transmission options and compatibility

The 350 small block paired with several automatic and manual transmissions depending on the vehicle and year. The Turbo 350 (TH350) three-speed automatic was the most common pairing in passenger cars and light trucks from the late 1960s through the 1980s. The Turbo 400 (TH400) four-speed automatic appeared in heavier trucks and performance vehicles. Both are robust and still widely used in hot rods and restorations.

Manual transmissions varied by process. The Muncie M20 and M21 four-speeds were common in 1960s and 1970s performance cars. The Saginaw four-speed appeared in later models. The T-10 four-speed and T-56 six-speed also paired with 350s in various applications. When sourcing a used 350 engine, verify which transmission your vehicle has or which one came with the engine you are buying, because bell housing patterns and bolt configurations differ between transmission families.

Rebuilding and modification costs

A basic 350 rebuild—removing the engine, boring the block, honing the cylinders, replacing pistons and rings, and reassembling with new gaskets and seals—typically costs $1,500 to $3,000 in labor, plus parts. Parts for a stock rebuild (pistons, rings, bearings, gaskets, seals) run $400 to $800. A machine shop will charge $300 to $600 to bore and hone the block, depending on how much material needs to be removed.

Performance modifications cost more. A mild cam upgrade with new valve springs and pushrods adds $400 to $800. Ported and polished cylinder heads run $600 to $1,200 per pair. A performance intake manifold costs $300 to $600. A complete performance rebuild with forged pistons, a performance cam, ported heads, and a tuned carburetor or fuel injection system can reach $4,000 to $6,000 in parts and labor combined. Because 350 parts are abundant, these costs are lower than for most other V8 engines.

Finding and buying a used 350 engine

Used 350 small blocks are available from salvage yards, online marketplaces, engine rebuilders, and private sellers. Salvage yards typically charge $400 to $800 for a complete engine with accessories, depending on mileage and condition. Online marketplaces like eBay Motors and Craigslist often list engines ranging from $300 to $1,200. Rebuilt engines from specialty shops cost $1,500 to $2,500 and usually come with a warranty.

When buying a used 350, inspect for oil leaks, corrosion, and damage to the block or heads. Listen for valve train noise—a persistent ticking suggests worn valve lifters or pushrods. Ask about the engine's history: how many miles, what vehicle it came from, whether it ran when removed, and whether any work was done recently. Request photos of the engine bay and the block's casting date, which is stamped on the side of the block and helps identify the year and original process. A compression test performed by a shop before purchase reveals whether the rings and valves are still sealing properly.

Frequently Asked Questions

How much does a 350 small block weigh?

A 350 small block weighs approximately 575 pounds dry (without fluids). With oil, coolant, and other fluids, the weight increases to around 650 pounds. This relatively light weight for a V8 is one reason the 350 became popular in performance cars and hot rods.

Can I swap a 350 into a different vehicle?

Yes, 350 swaps are common in hot rods and restorations. The engine's compact dimensions allow it to fit in engine bays designed for earlier small blocks. However, you will need to verify that the motor mounts, transmission bellhousing, radiator, cooling fan, and fuel system are compatible with your specific vehicle. Electrical connections and emission control systems also vary by year and process.

What octane fuel should I use in a 350?

Most stock 350s run on regular 87-octane fuel without issues. High-compression performance versions (10.0:1 or higher) benefit from 91 or 93-octane fuel to prevent pinging under load. Check your vehicle's owner manual or the fuel door for the manufacturer's recommendation. Using lower octane than recommended can cause detonation, which damages the engine over time.

How often should I change the oil in a 350?

Follow your vehicle's owner manual, but most 350s benefit from an oil change every 3,000 to 5,000 miles with conventional oil, or every 7,500 to 10,000 miles with synthetic oil. Older engines with higher mileage may need more frequent changes because wear increases oil contamination. If you drive in dusty conditions or tow regularly, change oil more often.

Is the 350 still a good engine to buy today?

Yes, for specific purposes. The 350 remains affordable to buy, rebuild, and modify. It is reliable when maintained and produces adequate power for most applications. However, modern engines are more fuel-efficient and produce more horsepower per liter. A 350 makes sense if you are restoring a classic vehicle, building a hot rod, or need an inexpensive V8 for a project car.