What Does It Mean When A Car Has A '345 Hemi' Badge On It? Here's The Answer

There are several different ways that automakers classify the engines that they make. In many cases, they just give the engines cool names, such as Ford with its Coyote and Voodoo engines. However, most of the time, they are given names based on the volume of the engine's displacement. You may think that this size is determined by the combustion chamber, but it is actually determined by how much air an engine is able to displace with its cylinders. To figure out the actual displacement of the engine, you need to know three important numbers: the number of cylinders your engine has, the bore (the diameter of the piston), and the stroke (the distance the piston travels).

Depending on which measurement system you are using, the volume of your engine displacement will be calculated in one of three ways: liters, cubic centimeters, or cubic inches. In the United States, engine displacement is typically shown in liters, even though it's a country that tends to avoid the metric system. Take the Hemi engines that powered the likes of many Chrysler, Dodge, Jeep, and Ram vehicles up through 2023 when they were discontinued. The Hemi name comes from the fact that these are hemispherical engines, and to distinguish between the different Hemis, it used liters, such as the 6.4L Hemi.

However, you may be on the road and see a vehicle with a badge that reads "345 Hemi." This does not mean that the engine displacement volume is 345 liters. Instead, these car owners want to show off their 5.7L Hemi V8 engine in a different way.

The 5.7L Hemi is a V8 engine with a bore and stroke of 3.917 inches by 3.578 inches, respectively. That means that the engine displacement could also be categorized as 345 cubic inches, which is where people are getting the number for their 345 Hemi badges on their vehicles. However, these badges are not coming directly from the factory on someone's Ram 1500 or Dodge Challenger. If these vehicles have the 5.7L Hemi V8 under the hood, then the badge these companies put on them indicate either the 5.7L Hemi or simply that it has a Hemi engine. Instead, the 345 badge is one that car owners have chosen to put on their vehicles from third-party sellers like Natalex Auto.

The appeal for wanting the cubic-inch designation rather than liter comes from the heyday of the muscle car when every engine was measured in cubic inches in the United States. It wasn't until the '70s and '80s that automakers converted to the metric system due in no small part to the Metric Conversion Act of 1975 and the Omnibus Trade and Competitiveness Act of 1988, which have resulted in a country that uses either imperial or metric measurements without much consistency. For some gearheads, putting the 345 Hemi badge on their car is a shoutout to automobile history, and if it mirrors that muscle-car era, their own car comes across as a more powerful machine than if it had a 5.7L badge on it.

[Image by Ermell via Wikimedia Commons | Cropped and scaled | CC BY-SA 4.0]