How much horsepower can you get out of a built 350 small-block?
In short, a built 350 small-block can deliver roughly 300–350 hp in a mild street setup, climb to about 450–550 hp with well‑chosen components and modern heads, and push well beyond 600 hp with strokers or forced induction. The exact figure depends on how you assemble the engine and what you pair it with for induction and fueling.
This article dives into the typical horsepower targets for the 350 small-block, the major variables that influence output, and practical boundaries for street use versus high-performance applications, including naturally aspirated builds, stroked variants like the 383, and boosted configurations.
Understanding the baseline
The Chevrolet 350 small-block has a storied lineage and a vast aftermarket ecosystem. With a displacement of 5.7 liters, it responds strongly to improved airflow, compression, and a refined fuel and ignition strategy. Final horsepower is shaped by head design, cam timing, induction, exhaust, and the engine’s internals and tuning.
NA horsepower ranges for common 350-based builds
Below are representative ranges for naturally aspirated builds that stay within pump-gas limits and street drivability. The numbers assume good heads, a reasonable cam, and proper tuning.
- Mild street rebuild with stock or reasonable upgrades: 300–350 hp
- Popular performance street build with better heads and cam: 350–450 hp
- High-performance NA build with ported heads and aggressive cam: 450–520 hp
- Stroked 383 variant (350-based) with higher compression and optimized intake: 420–520 hp
These figures vary widely based on head choice (iron vs aluminum), compression, intake, exhaust, fuel, and the rev range in which the engine is designed to perform.
Key factors that influence horsepower
Horsepower is the product of airflow, fuel delivery, and ignition efficiency. The primary levers are:
- Displacement and stroke (including stroker kits like 383 or larger)
- Cylinder heads (flow, porting, material)
- Compression ratio and fuel type
- Camshaft profile and valve train (lift, duration, LSA)
- Induction system (carb vs EFI, single-Plane vs dual-Plane intake)
- Exhaust system (headers, exhaust diameter, collector design)
- Fuel and ignition management (EFI tuning, timing, fuel pressure)
In practice, optimizing these factors yields higher horsepower but may affect driveability, emissions, and reliability if not coordinated with intended use and fuel quality.
NA vs boosted: where the horsepower numbers land
Naturally aspirated (NA) targets
For naturally aspirated builds, the upper end is typically guided by head design and compression. A well‑designed 350 with modern aluminum heads, a solid intake, and a cam tuned for a healthy RPM range can reach roughly 450–550 hp in well‑tuned combinations. A practical, streetable target around 500 hp is achievable with high-flow components and careful tuning on pump gas.
Stroked and optimized NA builds
Stroking the engine to 383 cubic inches (or larger) increases torque and potential horsepower. A 383‑based NA setup with good heads and compression can produce roughly 450–550 hp, depending on head flow and rev limits. Some high‑end builds push beyond 550 hp, but achieving that level requires premium parts and precise tuning.
Boosted and high-performance routes
Forced-induction options
Boosted 350 small-blocks can deliver substantial power gains. A turbocharged or supercharged 350 with forged internals and a robust fuel system can range from about 600–1000+ hp, depending on turbo sizing, boost level, and engine internals. A common street-oriented target is roughly 700–800 hp with manageable driveability and pump gas on modest boost.
Budget and reliability considerations
As power climbs, the required supporting systems grow: stronger bottom end, upgraded oiling and cooling, precise fuel and ignition control, and proven tuning. Reliability hinges on choosing the right components for your intended use and ensuring the engine can sustain the chosen power level under real-world driving conditions.
What it takes to reach high horsepower on a 350
Parts and tuning basics
Reaching higher horsepower generally requires a combination of these elements: high-flow cylinder heads (often aluminum), a cam profile tailored to your RPM range, a capable intake and exhaust setup, appropriate compression, and precise engine management. For boosted builds, expect forged internals and a validated boost strategy.
- Head choice: optimized flow, aluminum vs iron
- Cam and valvetrain: duration, lift, LSA tuned for rpm
- Intake and exhaust: high-flow intake, headers, appropriate exhaust diameter
- Compression and fuel: pump gas-friendly vs race gas; reliable timing maps
- Bottom end: forged pistons/rods if boosting, with reinforced oiling
In practice, the horsepower ceiling is set by how effectively the engine can move air and sustain timing and fueling under load, while staying within mechanical and thermal limits.
Bottom line for builders and enthusiasts
Practical expectations for street-ready builds
For most enthusiasts building a 350 for street use, aiming for a reliable 450–500 hp NA with pump gas is a common, satisfying target. If you want higher numbers, plan for a stroked variant and/or forced induction, with attention to cooling, fuel delivery, and driveline strength to maintain daily drivability.
Summary
Built 350 small-blocks offer a broad horsepower spectrum, from a solid 300–350 hp for a mild restoration to 450–550 hp in optimized naturally aspirated builds, and well into 600–1000+ hp with forced induction. The exact output hinges on displacement (including stroker options like the 383), cylinder head choice, compression, cam timing, induction, exhaust, and tuning. For many enthusiasts, a practical target sits around 500 hp NA on pump gas or 700–800 hp with boost, balancing power with reliability and daily usability.
Is a 327 more powerful than a 350?
The bottom line here is simple; no matter what you do to a 327, if you do the same thing to a 350, it WILL make more horsepower and torque than a 327 will, period. The same thing goes with ANY engine when comparing cubic inches and power, especially when you are talking about making more torque with longer strokes.
How much HP can a 350 small block make?
A Chevy 350 small block can produce anywhere from 140 to over 570 horsepower, depending on its age, specific build, and modifications. Stock versions have a wide range, but a properly modified and tuned 350 can easily make 300-400 hp, and even 500+ hp with a high-end build that includes performance heads, a strong camshaft, and other upgrades.
Typical horsepower ranges
- Stock (factory): Factory-rated horsepower for stock 350s ranges from approximately 140 hp to 375 hp, varying significantly by model year and vehicle application.
- Budget-friendly modifications: With basic upgrades like improving the intake and exhaust ("breathing") and a mild cam, you can expect to reach around 300 hp.
- Performance builds: A more performance-oriented build with better heads, a more aggressive cam, and other components can achieve 350 to 400 hp.
- High-end builds: Building a 350 for maximum power can push it to 500 hp or even higher, especially when using forced induction like turbochargers or superchargers.
Factors influencing horsepower
- Components: The specific components you choose, such as the heads, camshaft, intake manifold, and carburetor/fuel injection system, have the largest impact on horsepower output.
- Engine balance and strength: For higher-horsepower builds, the engine's internal components need to be balanced, and it's important to consider the strength of the block, crank, and rods to handle the extra stress.
- Tuning: Proper tuning, including ignition timing and air-fuel ratio adjustments, is crucial for both achieving maximum power and ensuring reliability.
How to get the most HP out of a Chevy 350?
Two-Barrel Carb to a Four: Upgrading your Chevy 350's stock two-barrel carburetor to a four-barrel, like a Holley 650 double pumper, is a great way to add more horsepower.
How much power can a 4 bolt main 350 handle?
He amount of power they will make depends on how deep your pockets are. You're likely to hear everything from 500 to 1000 HP on these forums. How much power it can hold is going to depend on a few different things like how well the engine is balanced and how well you're able to control detenation.
