The 5.7 HEMI is a 5.7-liter V8 engine whose displacement is commonly cited as 345 cubic inches. The number 392 refers to the 6.4-liter HEMI, not the 5.7. In short, a 5.7 HEMI is 345 cubic inches, while 392 identifies a different, larger engine.
Displacement explained: liters vs cubic inches
Engine displacement is reported in both liters (L) and cubic inches (ci). In Chrysler’s HEMI family, the 5.7 L engine is officially listed as 345 cubic inches, while the larger 6.4 L engine is listed as 392 cubic inches. The two measurements reflect rounding and branding conventions that have stuck in consumer and dealer materials.
- 5.7 L HEMI displacement: 345 cubic inches (about 5.7 liters).
- 6.4 L HEMI displacement: 392 cubic inches (about 6.4 liters).
- The bore and stroke configuration of the 5.7 HEMI yields roughly 345 ci per official specifications; the 6.4 L is similarly rounded to 392 ci in marketing and documentation.
- Branding and badges typically align with these rounded figures, helping buyers distinguish the engine size at a glance.
Conclusion: The 345 cubic inches refers to the 5.7 HEMI, while 392 cubic inches refers to the 6.4 HEMI. These numbers are used in badges, spec sheets, and marketing to differentiate the engines within the HEMI lineup.
Where you’ll find each engine in vehicles
Different Dodge/Chrysler/Jeep models use different HEMI displacements, with the 5.7 HEMI commonly appearing in mainstream performance and pickup models and the 6.4 HEMI reserved for higher-performance variants. Here’s a quick guide to typical applications:
- 5.7 HEMI: widely used in Ram 1500 pickups, and in performance variants of the Dodge Challenger and Charger, as well as other Chrysler group models over the years.
- 6.4 HEMI (392): used in high-performance versions such as the Dodge Challenger SRT 392 and Dodge Charger Scat Pack 392, among others.
Note: Model-year availability varies by region and trim level, so always verify the engine displacement on the specific vehicle’s badge or official spec sheet.
Additional context and caveats
Beyond the basic 345 vs 392 distinction, there are other HEMI variants and related displacements in the broader family. For example, there are smaller displacements in the modern Pentastar lineup and older HEMI variants with different bore/stroke configurations. When in doubt, check the VIN, the build sheet, or the official dealer specs to confirm the exact engine in a given vehicle.
Summary
In summary, the 5.7 HEMI is a 345-cubic-inch engine (approximately 5.7 liters). The 392 designation belongs to the larger 6.4-liter HEMI engine, which has a displacement of 392 cubic inches. They are distinct engines used in different performance and capacity tiers within Dodge/Chrysler’s HEMI lineup.