Bore, stroke, displacement and compression for all 15 Oldsmobile Rocket engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 260–455 ci |
|---|---|
| Cylinders | 8 |
| Bore | 3.700–4.125" |
| Stroke | 3.060–4.300" |
| Compression | 8.0–10.5:1 |
| Advertised power | 110–370 hp |
| Years | 1980–1988 |
| Cylinder head data | 1 of 15 engines |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| 455 | 455 ci | 4.1252" × 4.3" | 10.5:1 | 370 |
| 425 | 425 ci | 4.1252" × 4" | 10.25:1 | 360 |
| 403 | 403 ci | 4.1252" × 3.75" | 8:1 | 185 |
| 400 | 400 ci | 4.0598" × 3.9" | 10.5:1 | 340 |
| 400 | 400 ci | 4.06" × 3.9" | 10.5:1 | 345 |
| 400 (Small Block) | 400 ci | 3.87" × 4.25" | 10.5:1 | 325 |
| 394 | 394 ci | 4.0598" × 3.8" | 9.75:1 | 315 |
| 371 | 371 ci | 4" × 3.7" | 9.25:1 | 277 |
| 350 | 350 ci | 4" × 3.5" | 9:1 | 250 |
| 330 | 330 ci | 3.938" × 3.385" | 9:1 | 260 |
| 324 | 324 ci | 3.8752" × 3.5" | 8.5:1 | 185 |
| 307 | 307 ci | 3.8" × 3.35" | 8:1 | 140 |
| LV2 | 307 ci | 3.8" × 3.35" | — | 140–155 |
| 303 | 303 ci | 3.75" × 3.4375" | 8:1 | 135 |
| 260 | 260 ci | 3.7" × 3.0598" | 8:1 | 110 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
Compression spans 8:1 to 10.5:1, so fuel requirements differ meaningfully between members — worth checking before assuming parts interchange.
The family mixes oversquare and undersquare designs, so members behave quite differently despite sharing a name.
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.