Did Chevy make a 405 engine?
Chevrolet did not produce a factory engine with a 405 cubic-inch displacement. The 405 figure you might encounter in discussions is more likely a reference to horsepower ratings or a misreading of displacement numbers, not a true 405 cu in engine. This article sorts out what does exist in Chevrolet’s history and why the 405 figure can appear in chatter.
Context: Chevrolet’s actual engine displacements
To understand where “405” might come from, it helps to look at the actual factory displacements Chevrolet built over the decades. The company produced a wide range of V8s, but the official cubic inches didn’t include a 405 in any production lineup. Below are the common displacements you’ll see in Chevrolet’s historic engines, which helps explain why 405 is a misnomer in most conversations.
- Chevrolet small-block displacements: 265 cu in, 283 cu in, 327 cu in, 350 cu in, and a 400 cu in variant that appeared in the late 1960s/early 1970s era.
- Chevrolet big-block displacements: 396 cu in, 409 cu in, 427 cu in, and 454 cu in are among the best-known large-displacement options from Chevrolet’s classic lineup.
These are the factory-displacement figures you’ll see in catalogs, service manuals, and vintage advertisements. The “405” figure tends to show up only as either a numerical misread or as a reference to horsepower—not the engine’s displacement itself.
Why the number 405 appears in discussions
Several factors contribute to the persistence of the 405 figure in online forums and vintage literature. Understanding these can help distinguish fact from folklore.
- Horsepower vs displacement: In era-specific advertisements, engines were rated for horsepower that sometimes landed near the 400-range. Enthusiasts may recall “about 405 horsepower” for certain high-performance variants, but that refers to power output, not to displacement.
- Gross vs net ratings: Before the early 1970s, GM used gross horsepower ratings under different testing standards than the later SAE net ratings. This mismatch can make horsepower claims appear inconsistent when comparing sources from different years.
- Model-year and option variations: Within a given V8 family, different cam profiles, carburetion, and exhaust setups produced a range of outputs. People sometimes quote a high-water mark in a way that gets remembered as “the engine was 405.”
In short, the confusion generally stems from horsepower discussions or catalog quirks rather than a true 405 cubic-inch Chevrolet production engine.
Notable engine families that are often mistaken for a 405 option
To illustrate the landscape, here are the Chevrolet engine families most often discussed by enthusiasts. None of these have a factory displacement of exactly 405 cu in, but they are the ones people often mix up when the topic of a “405 engine” arises.
- Small-block family: 265, 283, 327, 350 cu in (with a later 400 cu in variant in some eras)
- Big-block family: 396, 409, 427, 454 cu in
Because these are the canonical displacements, any reference to a 405 cu in engine almost always reflects confusion with horsepower figures or a miscommunication about year/model specifics.
Summary
Bottom line: Chevy did not manufacture a production engine with a 405 cubic inches displacement. The company’s storied V8 lineup includes several well-known displacements, notably 265–350 cu in for small-blocks and 396–454 cu in for big-blocks, with occasional 400 cu in variants in certain periods. When you encounter “405” in discussions, it’s more often a horsepower or rating quirk than a true 405 cu in engine. As always with classic muscle, the exact figure depends on the year, model, and rating method used in the source.
