GMC 400ci specs: 4.125 x 3.75 in (104.8 x 95.3 mm) bore and stroke. Displacement, compression and factory ratings for each, plus rod ratio and piston speed.
| Displacement | 400 ci |
|---|---|
| Cylinders | 8 |
| Bore | 4.125" |
| Stroke | 3.750" |
| Advertised power | 175–185 hp |
| Years | 1977–1979 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| LF4 | 400 ci | 4.125" × 3.75" | — | 175–185 |
This family is represented by a single engine in the database: 400 ci, 8 cylinders, a 4.125" × 3.75" 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.