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Cadillac LT8 specs: 249 ci (4.1L) 8-cylinder, 3.465 x 3.307 in (88 x 84 mm) bore and stroke. Rated 125-130 hp, 1982–1987. Used in the Cadillac Eldorado.
The Cadillac 249ci (LT8) is close to square: 3.465" bore against 3.307" stroke, within 4.8%, which splits the difference between a high-revving layout and a torque layout. The 3.307" stroke does not reach 4,000 ft/min of mean piston speed until about 7,250 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 8 cylinders displaces 31.1 ci (510 cc).
7 factory variants share these dimensions, rated from 125 to 130 hp across 1982–1987.
| Displacement | 249 ci / 4.1 L |
|---|---|
| Bore | 3.465" |
| Stroke | 3.307" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 8.5–9:1 (published figures vary) |
| Bore/stroke ratio | 1.048 |
| Fuel type | gas |
|---|---|
| Advertised HP | 125–130 hp |
| Years | 1982–1987 |
| Bore/stroke character | 1.048 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,307 ft/min — conservative for a street engine |
| Displacement per cylinder | 31.1 ci |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1982 | — | LT8 |
| 1982 | 125 hp | LT8 |
| 1983 | — | LT8 |
| 1984 | — | LT8 |
| 1985 | — | LT8 |
| 1986 | 130 hp | LT8 |
| 1987 | 130 hp | LT8 |
3 factory vehicles, 1982–1987. Each year opens that model's engine table.