Bore, stroke, displacement and compression for all 4 Oldsmobile Rocket V8 engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 303–394 ci |
|---|---|
| Cylinders | 8 |
| Bore | 3.750–4.126" |
| Stroke | 3.437–3.685" |
| Compression | 7.5–10.3:1 |
| Advertised power | 135–315 hp |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| 394 | 394 ci | 4.126" × 3.685" | 10.25:1 | 315 |
| 371 | 371 ci | 4" × 3.685" | 9.25:1 | 277 |
| 324 | 324 ci | 3.874" × 3.437" | 8.25:1 | 185 |
| 303 | 303 ci | 3.75" × 3.437" | 7.5:1 | 135 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
Compression spans 7.5:1 to 10.25:1, 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.