GMC 307ci specs: 3.875 x 3.25 in (98.4 x 82.6 mm) bore and stroke. Displacement, compression and factory ratings for each, plus rod ratio and piston speed.
| Displacement | 307 ci |
|---|---|
| Cylinders | 8 |
| Bore | 3.875" |
| Stroke | 3.250" |
| Advertised power | 135–200 hp |
| Years | 1970–1972 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| L14 | 307 ci | 3.875" × 3.25" | — | 135–200 |
This family is represented by a single engine in the database: 307 ci, 8 cylinders, a 3.875" × 3.25" bore and stroke.
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.