What makes a Chevy engine a big block?

A Chevy big block engine is a type of V8 engine that is known for its large displacement and powerful performance. These engines have been a staple in Chevrolet vehicles for decades, offering impressive power and torque for a variety of applications.

Defining a Big Block Engine

The term "big block" refers to the physical size of the engine block, which is larger than a standard small block Chevy engine. The key distinguishing features of a big block Chevy engine include:

• Larger Displacement: Big block Chevy engines typically have a displacement ranging from 396 cubic inches (6.5 liters) up to 454 cubic inches (7.4 liters), compared to small block engines which are usually 350 cubic inches (5.7 liters) or less.


• Larger Cylinder Bores: The cylinder bores in a big block engine are larger in diameter, allowing for more air and fuel to be packed into each cylinder.


• Heavier Construction: The engine block, heads, and other components are built more sturdily to handle the increased power and torque output.

These design elements allow big block Chevy engines to produce significantly more horsepower and torque than their small block counterparts, making them a popular choice for high-performance applications like muscle cars, hot rods, and racing vehicles.

History of the Chevy Big Block

Chevy first introduced the big block engine in 1958 with the 348 cubic inch W-series engine. This was followed by the legendary 396 cubic inch big block in 1965, which became one of the most iconic muscle car engines of the era. Over the years, Chevy continued to develop and refine the big block design, culminating in the massive 454 cubic inch LS6 engine that powered the Chevelle SS in 1970.

While big block engines fell out of favor in the 1970s and 80s due to emissions regulations and the push for more fuel-efficient engines, they have experienced a resurgence in popularity among enthusiasts in recent decades. Today, Chevy continues to offer big block crate engines and performance parts for those looking to build high-powered custom vehicles.

Key Advantages of the Chevy Big Block

The primary advantages of a Chevy big block engine include:

• Increased Power and Torque: The larger displacement and cylinder bores allow big block engines to produce significantly more horsepower and torque than small block engines, often in the range of 400-500 hp or more.


• Durability: The heavy-duty construction of big block engines makes them well-suited for high-performance applications and heavy-duty use.


• Customization: The big block design provides more flexibility for engine builders and enthusiasts to modify and tune the engine for their specific needs.

While big block engines may not be as fuel-efficient as their smaller counterparts, their raw power and performance make them a favorite among Chevy enthusiasts who prioritize driving excitement and high-octane thrills.

What counts as a big block in V8?

Though big-block engines are significantly larger than their small-block brethren, the true difference between these two is more about displacement, bore, and stroke than strictly size. Typically, big-block engines have displacements of greater than 400 cubic inches and small block engines have a smaller displacement.

What is considered a big block chevy?

A "Big Block Chevy" refers to a series of large-displacement, high-torque V8 engines produced by Chevrolet. They are physically larger than their small-block counterparts, designed with a bigger block, heads, and crankshaft to handle higher power outputs, which made them popular for heavy cars, trucks, and performance applications like muscle cars. Key models include the 348, 396, 427, and 454 cubic inch engines.
 
This video explains the differences between big block and small block engines: 1mNate RiderYouTube · Jun 2, 2024
Key characteristics of a Big Block Chevy:

• Physical size: They have a larger and taller block compared to small-block engines, allowing for greater displacement and strength. 
• Displacement: While a general rule is over 400 cubic inches (6.6 liters), some engines like the 396 are considered big blocks despite having a smaller displacement. 
• Power and torque: Their size enables them to produce significant power and torque, making them ideal for applications requiring heavy-duty performance. 
• History: The first production model was the 348 cubic inch engine in 1958. Over the decades, they evolved through various series (W-series, Mark IV) and displacements, with the 454 being a prominent example introduced in 1970. 
• Applications: Initially designed for heavy trucks and large passenger cars, they were also adopted for muscle cars to provide high performance, and were later used in boats, motorhomes, and other heavy-duty vehicles. 

You can watch this video to learn about the history of the Big Block Chevy: 59sRatMaroYouTube · Nov 5, 2020

How to tell a big block from a small block?

And you can have a 400 cubic inch small block and there's several other setups as well you know Fords if you get into the stroker Windsors you get a 408.

What classifies a motor as a big block?

A "big block" is a term for a large, physically bigger engine, historically defined by having a larger displacement, or swept volume, in its cylinders than a small block engine. Big block engines are known for producing more power and torque due to their larger bores and longer strokes, but they are heavier and less fuel-efficient. The distinction isn't always about displacement alone, but also the physical design of the engine block itself. 
This video explains the difference between big block and small block engines: 1mNate RiderYouTube · Jun 2, 2024
Key characteristics of big block engines

• Larger bore and stroke: The cylinders are wider (bore) and the pistons travel further up and down (stroke), creating more torque and horsepower. 
• Greater displacement: They have a larger overall engine volume, often exceeding 400400400 cubic inches, though specific ranges vary by manufacturer and model. 
• Heavier and bulkier: Big block engines have a larger physical footprint and are heavier, which can negatively impact a vehicle's handling. 
• Built for heavy-duty use: They were originally designed for heavy-duty applications like trucks and large passenger cars that needed more muscle. 
• More potential for power: Their larger design allows for bigger valves and ports, and they have more room to be modified for even greater performance. 

This video compares big and small block engines side-by-side: 1mUncle Tony's GarageYouTube · May 27, 2025
Big block vs. small block

• Power vs. Efficiency: Big blocks trade efficiency and fuel economy for brute power and torque. 
• Handling: The added weight of a big block can negatively affect a car's handling and acceleration, though the engine's power can overcome some of the performance drawbacks. 
• Physical size: The "big" in big block refers to its physical dimensions, such as the distance between cylinder bores, which is often a better defining characteristic than just the displacement number. 
• Modern engines: Today, many modern engines considered to be "big blocks" are actually small blocks with large displacement, or vice-versa. However, the term is still used to refer to engines with the older, larger architecture.