Oldsmobile 303ci specs: 3.75 x 3.438 in (95.3 x 87.3 mm) bore and stroke, shared by all 3 versions. Displacement, compression and factory ratings.
| Displacement | 303 ci |
|---|---|
| Cylinders | 8 |
| Bore | 3.750" |
| Stroke | 3.438" |
| Compression | 7.3–8.0:1 |
| Advertised power | 135–165 hp |
| Years | 1950–1953 |
| Cylinder head data | 3 of 3 engines |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| Oldsmobile 303ci · 3.75" × 3.438" · 7.25:1 | 303 ci | 3.75" × 3.438" | 7.25:1 | 135 |
| Oldsmobile 303ci · 3.75" × 3.438" · 7.5:1 | 303 ci | 3.75" × 3.438" | 7.5:1 | 145–160 |
| Oldsmobile 303ci · 3.75" × 3.438" · 8:1 | 303 ci | 3.75" × 3.438" | 8:1 | 150–165 |
All are oversquare — bore larger than stroke, which favours revs over low-end torque.
Each engine page carries rod ratio, mean piston speed, bore/stroke character and cylinder head specs where published, and links into the calculators with its dimensions already filled in.