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GMC Chevy Straight-6 (194/230/250/292) (1963–1965) specs: 230 ci (3.8L) 6-cylinder, 3.875 x 3.25 in (98.4 x 82.6 mm) bore and stroke. Rated 140 hp, 1963–1965.
The GMC Chevy Straight-6 (194/230/250/292) (1963–1965) is oversquare — the 3.875" bore exceeds the 3.25" stroke by 19.2% — a layout that favors airflow and RPM over leverage at the crank. The 3.25" stroke does not reach 4,000 ft/min of mean piston speed until about 7,400 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 38.3 ci (628 cc).
It is one of 10 engines in the Chevy Straight-6 (194/230/250/292) family, sitting between the 194 ci and 292 ci members. 3 factory variants share these dimensions, rated at 140 hp across 1963–1965.
| Displacement | 230 ci / 3.8 L |
|---|---|
| Bore | 3.875" |
| Stroke | 3.25" |
| Cylinders | 6 |
| Configuration | I6 |
| Bore/stroke ratio | 1.192 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 140 hp |
| Years | 1963–1965 |
| Bore/stroke character | 1.192 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,250 ft/min — conservative for a street engine |
| Displacement per cylinder | 38.3 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 |
|---|---|---|
| 1963 | 140 hp | — |
| 1964 | 140 hp | — |
| 1965 | 140 hp | — |