Bore, stroke, displacement and compression for all 2 GMC 122ci engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 121.9–122 ci |
|---|---|
| Cylinders | 4 |
| Bore | 3.268–3.386" |
| Stroke | 3.386–3.634" |
| Years | 2018–2023 |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| LTG | 122 ci | 3.3858" × 3.3858" | — | — |
| LSY | 121.9 ci | 3.2677" × 3.6339" | — | — |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
1 of 2 are undersquare — stroke larger than bore, favouring torque low in the range.
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.