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Chevrolet base specs: 140 ci 6-cylinder, 3.375 x 2.60 in (85.7 x 66 mm) bore and stroke, 8:1 compression. Rated 80-95 hp, 1960. Used in the Chevrolet Corvair.
The Chevrolet base is oversquare — the 3.375" bore exceeds the 2.6" stroke by 29.8% — a layout that favors airflow and RPM over leverage at the crank. The 2.6" stroke does not reach 4,000 ft/min of mean piston speed until about 9,250 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 23.3 ci (382 cc).
8:1 is low by modern standards and generally happy on regular pump fuel.
It is one of 4 engines in the Chevrolet 140ci family, all of them 140 ci — the differences between them are in compression, heads and rating, not displacement. 2 factory variants share these dimensions, rated from 80 to 95 hp in 1960.
| Displacement | 140 ci |
|---|---|
| Bore | 3.375" |
| Stroke | 2.6" |
| Cylinders | 6 |
| Compression ratio | 8:1 |
| Bore/stroke ratio | 1.298 |
| Fuel type | gas |
|---|---|
| Advertised HP | 80–95 hp |
| Years | 1960 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. | Duration int / exh | Valve lift int / exh | LSA |
|---|---|---|---|---|---|---|---|
| 1960 | gross | 80 @ 4400 | 125 lb-ft @ 2400 | 8:1 | 316° / 336° | 0.314" / 0.344" | 107° |
| 1960 | gross | 95 @ 4800 | 125 lb-ft @ 2800 | 8:1 | 352° | 0.380" | 108° |
Factory specification sheet. Durations are the factory's advertised figures at the basis printed on the sheet, not duration at .050" lift; lobe separation is calculated from the printed valve timing.
| Bore/stroke character | 1.298 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,600 ft/min — conservative for a street engine |
| Displacement per cylinder | 23.3 ci |
| Static compression | 8:1 — 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 |
|---|---|---|
| 1960 | 80 hp | base |
| 1960 | 95 hp | base |
1 factory vehicle, 1960. Each year opens that model's engine table.