6.5 liters is 396.7 cubic inches (6,500 cc) by straight math. Makers round, so the engines sold as 6.5 L measure from 394.1 to 396.6 cubic inches.
The most common: 396.6 ci (Chevrolet 396); 395.6 ci (Chevrolet 395 (6.2/6.5 Diesel V8)); 394.1 ci (Oldsmobile 394); 396.0 ci (GMC 396 (Big Block Chevy)).
| Engine | Codes | Years | Bore × stroke | Cubic inches | cc | Cylinders |
|---|---|---|---|---|---|---|
| Oldsmobile 394 | — | 1959–1964 | 4.124" × 3.688" | 394.1 | 6,458 | 8 |
| Chevrolet 396 | — | 1965–1969 | 4.094" × 3.766" | 396.6 | 6,499 | 8 |
| GMC 396 (Big Block Chevy) | — | 1968–1969 | 4.094" × 3.760" | 396.0 | 6,489 | 8 |
| Chevrolet 395 (6.2/6.5 Diesel V8) | L65, L56, L49, L49 / L57 | 1994–2004 | 4.060" × 3.820" | 395.6 | 6,483 | 8 (diesel) |
Cubic inches and cc are worked out from each engine's bore and stroke. Years are the model years of the factory cars on this site that list the engine.
Start with the engine code: on 1981-and-later cars and trucks it is a character of the VIN (the 8th on most American makes), and most blocks carry a code stamp. Each engine's page lists its codes and the cars it came in. See the VIN engine code lists by make.
396.7 cubic inches by straight conversion (1 liter = 61.024 cubic inches). Real 6.5 L engines measure 394.1 to 396.6 cubic inches; the table above lists each one.
6,500 cc by definition. The engines sold as 6.5 L range from 6,458 to 6,499 cc.
Makers name engines by rounded sizes. The real size comes from bore × bore × stroke × 0.7854 × cylinders, so two engines sold as the same size are often a few cubic inches apart.