Oldsmobile 215ci specs: 3.50 x 2.80 in (88.9 x 71.1 mm) bore and stroke, shared by all 4 versions. Displacement, compression and factory ratings.
| Displacement | 215 ci |
|---|---|
| Cylinders | 8 |
| Bore | 3.500" |
| Stroke | 2.800" |
| Compression | 8.8–10.8:1 |
| Advertised power | 155–215 hp |
| Years | 1961–1963 |
| Cylinder head data | 3 of 4 engines |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| Oldsmobile 215ci (1961–1963) | 215 ci | 3.5" × 2.8" | — | 185–215 |
| Oldsmobile 215ci · 3.5" × 2.8" · 8.75:1 | 215 ci | 3.5" × 2.8" | 8.75:1 | 155 |
| Oldsmobile 215ci · 3.5" × 2.8" · 10.25:1 | 215 ci | 3.5" × 2.8" | 10.25:1 | 185 |
| Oldsmobile 215ci · 3.5" × 2.8" · 10.75:1 | 215 ci | 3.5" × 2.8" | 10.75:1 | 195 |
Compression spans 8.75:1 to 10.75:1, so fuel requirements differ meaningfully between members — worth checking before assuming parts interchange.
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.