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Dodge 239ci (1988–1991) specs: 239 ci (3.9L) 6-cylinder, 3.909 x 3.311 in (99.3 x 84.1 mm) bore and stroke, 9.2:1 compression. Built 1988–1991.
The Dodge 239ci (1988–1991) is oversquare — the 3.9094" bore exceeds the 3.311" stroke by 18.1% — a layout that favors airflow and RPM over leverage at the crank. The 3.311" 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 6 cylinders displaces 39.8 ci (653 cc).
9.2:1 on iron heads is low by modern standards and generally happy on regular pump fuel.
It is one of 2 engines in the Dodge 239ci family, all of them 239 ci — the differences between them are in compression, heads and rating, not displacement. 4 factory variants share these dimensions across 1988–1991.
| Displacement | 239 ci / 3.9 L |
|---|---|
| Bore | 3.9094" |
| Stroke | 3.311" |
| Cylinders | 6 |
| Configuration | V6 |
| Compression ratio | 9.2:1 |
| Bore/stroke ratio | 1.181 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Firing order | 1-6-5-4-3-2 |
| Years | 1988–1991 |
| Bore/stroke character | 1.181 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,311 ft/min — conservative for a street engine |
| Displacement per cylinder | 39.8 ci |
| Static compression | 9.2:1 — low by modern standards, generally happy on regular pump fuel |
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 |
|---|---|---|
| 1988 | — | — |
| 1989 | — | — |
| 1990 | — | — |
| 1991 | — | — |
1 factory vehicle, 1988–1991. Each year opens that model's engine table.