Big Block Vs Small Block Engines - Whats The Difference?

With more than one hundred million engines manufactured and sold since 1955, small and big block engines have been a mainstay in American vehicles.

What is a big block engine?

Big block engines deliver increased power production with larger bores, valves, and ports than small block engines. They were originally designed for larger cars and trucks before being added routinely to most passenger vehicles. As it adds weight to a vehicle's front axle, it may sacrifice acceleration for power. For perspective, big block engines can hit 5500 RPMs.

What is a small block engine?

A small block engine is a miniature version of the big block engine with smaller bores, strokes, ports, and valves. They weigh less, which provides a boost to overall acceleration and handling. In terms of torque, they can generate up to 5800 RPM.

History of Production

Coined by Chevrolet to refer to large displacement V8 engines, 'big block' and 'small block' engines have powered its vehicles since the introduction of small block engines in 1950's Corvettes and Bel Airs. The small block V8 engine was well received for its agile combination of lighter weight and power, suited for hot rods and racing-inspired vehicles like the Corvette. Thanks to the small block V8, Corvette 0 to 60-mph launch times were significantly improved. As a result, other automakers such as Ford followed suit, manufacturing small block V8 engines for 60's models Fairlane, Windsor, and first-ever GT350.

In turn, big block engines were first introduced in 1958 as the Mark I or W series in response to increasing demand for passenger vehicles after World War II. These big block engines worked to power larger vehicles, including muscle cars.

Past and Current Uses

The decision between small block versus big-block engines ultimately comes down to power and torque versus acceleration and handling. Big block engines are constructed using iron (complete engine assembly of ~685 pounds), with Gen 5-7 big block engines capable of up to 700 horsepower. Small block engines weigh approximately 575 pounds and could handle about 550 horsepower with slight variance depending on the age of the block.

In terms of RPMs, big blocks usually have a cap of 5500 RPM, which is the limit due to its very heavy valvetrain. Small block engines come in a little higher (5800 RPM)

In short, big block engines deliver increased power at the expense of fuel economy, stiffer front springs, large wheels/tires, and engine bay space. They also require bigger brakes and allows for less room for cooling systems and accessory drives. Small block engines sacrifice power for being lighter weight and are generally less expensive to build with better fuel economy.

All in all, small block and big block engines form an integral part of your GM, Chevrolet, or Ford vehicle. With more than 100 million engines sold, it speaks to the longevity and history of this iconic piece of machinery powering our vehicles for generations.