Bore, stroke, displacement and compression for all 3 Oldsmobile V8 engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 330–455 ci |
|---|---|
| Cylinders | 8 |
| Bore | 3.937–4.126" |
| Stroke | 3.382–4.252" |
| Compression | 9.0–10.3:1 |
| Advertised power | 230–365 hp |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| 455 | 455 ci | 4.126" × 4.252" | 10.25:1 | 365 |
| 400 V8 Early | 400 ci | 4" × 3.9724" | 10.25:1 | 345 |
| 330 | 330 ci | 3.937" × 3.3819" | 9:1 | 230 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
1 of 3 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.