Bore, stroke, displacement and compression for all 8 Oldsmobile Quad 4 engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 138–146 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.543–3.622" |
| Stroke | 3.346–3.701" |
| Compression | 9.5–10.0:1 |
| Advertised power | 150–190 hp |
| Years | 1988–2017 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| LD9 | 146 ci | 3.5433" × 3.7008" | 9.5:1 | 150 |
| LAF | 146 ci | 3.5433" × 3.7008" | — | 182 |
| LUK | 146 ci | 3.5433" × 3.7008" | — | 182 |
| LEA | 146 ci | 3.5433" × 3.7008" | — | 182 |
| LD9 | 146 ci | 3.5433" × 3.7008" | — | 150 |
| LD2 | 138 ci | 3.622" × 3.3465" | 9.5:1 | 150 |
| Quad 4 · 3.622" × 3.346" · 10:1 | 138 ci | 3.622" × 3.3465" | 10:1 | 180–190 |
| LD2 | 138 ci | 3.622" × 3.3465" | — | 150–160 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
3 of 8 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.