Who Makes 10.3 Liter Big Block Engines Besides Chevy?

Chevrolet's ZZ632 big block engine may be the most recognizable crate engine in the 10.3-liter displacement class, with a price of around $34,000. But it isn't the only 632ci big block available. Specialty engine builders like Prestige Motorsports and Steve Morris Engines can produce 632ci combinations, which are roughly equivalent to 10.3 liters. Meanwhile, several established performance engine manufacturers also offer their own 632ci engines as cataloged products.

For example, BluePrint Engines offers a 632-cubic-inch GM big-block-compatible Pro Series engine with 815 horsepower and 775 pound-feet of torque. Known as the Blackout Reaper Edition, it uses a 4.600-inch bore, 4.750-inch stroke, aluminum cylinder heads, and forged crankshaft and pistons. This engine with a 4L80E transmission costs $30,899. Additionally, Nelson Racing Engines has a 632-cubic-inch naturally aspirated big block V8 engine through its Hot Rod Series. The engine features a Dart block and forged internal components with an output of more than 850 horsepower. Prices for this engine start at $27,000.

Then there's ATK High Performance Engines, which has a 632-cubic-inch Pro Street V8 rated at 820 horsepower, 800 pound-feet of torque, and it costs $16,999. The engine has a Dart Big M block, forged crankshaft, connecting rods and pistons, aluminum cylinder heads, and a hydraulic roller camshaft. Lastly, there's the Shafiroff 632-cubic-inch UltraStreet Big Dawg that combines a tall-deck block with forged steel components, producing 945 horsepower and 845 pound-feet of torque. This engine, before carburetor and ignition, costs $18,950.

The 10.3-liter big block Chevrolet engine is one of the most powerful engines you can buy. But while it's in the same displacement class as some aftermarket engines, that doesn't mean they're identical. Chevrolet's ZZ632/1000 produces 1,004 horsepower and 876 pound-feet of torque on 93-octane pump gas. It uses electronic fuel injection, a crank-trigger ignition system, forged internal components, and RS-X spread-port cylinder heads. It's also built around a tall-deck Sportsman Bowtie block. This design gives the Chevy engine a specific combination of factory parts that may not be found in other 632ci engines.

Origin Engines takes the 10.3-liter big block engine design in a completely different direction, using it for industrial applications instead of street or racing vehicles. The company's spark-ignited V8 is available in natural gas, propane, or gasoline configurations, along with naturally aspirated and turbocharged versions available as well. Origin designed the 10.3-liter engine to deliver performance on par with Tier 4 and gas-diesel engines.

if you're wondering why 632-cubic inch engines aren't used in everyday vehicles, it's because of their design. These engines are built around extreme performance rather than the balance of power and efficiency found in modern production vehicles. While the EPA hasn't addressed these engines directly, it has noted that increases in power, weight, and size are likely to result in lower fuel economy. This makes an engine like the ZZ632 a poor fit for a typical factory-installed powertrain, though it is one of several engines that outpaces modern turbocharger tech.