How much horsepower does a 350 Big-Block Chevy have?
There isn’t a Chevrolet factory engine officially labeled as a “350 Big-Block.” The 350 cubic inch displacement is the hallmark of Chevrolet’s small-block family, and horsepower figures vary widely depending on era, configuration, and tuning. In short: the label doesn’t describe a true big-block Chevy, and output depends on the specific engine.
This article clarifies the confusion around the 350 designation, explains how big-block and small-block families differ, and outlines typical horsepower ranges from classic cars to modern LS-era engines. It also touches on what you can expect if you’re shopping for horsepower today.
The 350: Big-Block or Small-Block?
Chevrolet’s “350” designation is historically tied to the small-block V8 family. The big-block family uses larger displacements such as 396/402/427/454 and related bore/stroke configurations. If you encounter a “350 Big-Block,” it’s usually a mislabel or a heavily modified engine rather than a factory Chevrolet product. Below are key points that help sort the terminology and the horsepower expectations.
- Big-block vs small-block architecture: deck height, bore spacing, and internal components differ, affecting strength, weight, and horsepower potential.
- Displacement naming: 350 typically refers to 350 cubic inches in the small-block lineage; Chevrolet’s big-blocks are named by larger displacements (e.g., 396/427/454).
- Stock horsepower varies by era: early small-blocks often produced lower numbers due to emissions and tuning shifts, while modern small-blocks (including LS-family engines) push higher outputs in stock form with modern technology.
In practice, the phrase “350 Big-Block” is not a reliable descriptor of a factory Chevrolet engine. The horsepower you see quoted for a “350” will depend on whether the engine is a classic small-block, a modern LS-based variant, or a crate/modified build. The takeaway is that the displacement tag alone doesn’t determine whether an engine is big-block or small-block, and it shouldn’t be treated as a horsepower guarantee.
Horsepower ranges by era
Here’s a quick look at typical factory horsepower figures associated with Chevrolet 350-class engines across different generations. Note that testing standards (gross vs net) and emissions controls affect the numbers, so comparisons aren’t always apples-to-apples.
- Late 1960s to early 1970s small-block 350: commonly in the roughly 250–300 horsepower range in many street configurations.
- 1980s emissions-era small-blocks: often lower, around 190–260 horsepower, due to stricter emissions and fuel-management changes.
- 1990s onward (LS-family and other modern small-blocks around 350 ci): typically about 300–360+ horsepower in stock form, with higher-performance variants exceeding 400 horsepower.
- High-performance or crate options: factory-tagged crate engines and modern builds can push well beyond 450 horsepower, depending on induction, compression, and boost or nitrous setups.
Conclusion: There is no Chevrolet-issued “350 Big-Block.” Horsepower figures for a 350-class engine depend on era, configuration, and whether the engine uses traditional carburetion or modern fuel-injection and tuning. In contemporary settings, small-blocks (including LS-based 346–350 ci variants) commonly sit in the 300–360 hp range, with performance variants stretching higher.
What to consider if you want more horsepower today
If your goal is more horsepower from a 350-based setup, several practical paths exist, ranging from crate engines to modern swaps, each with its own pros and cons.
- Crate engine options from GM Performance Parts and similar suppliers offer reliable, tuned packages that boost horsepower without reinventing the wheel. Examples include modern small-block crate motors with outputs in the 355–475+ hp range, depending on configuration.
- Modern LS-based swaps (e.g., 5.7L/346 ci family and newer) provide substantial power gains, improved efficiency, and modern fuel-management systems, often with better drivability than older carbureted setups.
In practice, upgrading horsepower today often involves choosing a modern small-block or LS-based platform, then selecting crate options or a swap that aligns with your performance goals and budget. Proper supporting components (intake, exhaust, cam, fuel system, and tuning) are essential to realize the horsepower gains safely and reliably.
Summary
There is no factory Chevrolet engine officially designated as a “350 Big-Block.” The 350 cubic-inch displacement is a hallmark of Chevrolet’s small-block family, and horsepower figures vary widely by era, configuration, and whether the engine uses carburetion or modern fuel-injection. Classic small-blocks generally fall in a broad 250–360 hp spectrum, with higher-performance variants and crate/modern LS-based builds pushing beyond 400 hp. If you’re chasing horsepower today, crate motors and LS-based swaps offer practical, well-supported paths to substantial gains, while the notion of a true “350 Big-Block” remains a misnomer rather than a factory reality.
