Bore, stroke, displacement and compression for all 6 GMC High Feature V6 engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 169–222.7 ci |
|---|---|
| Cylinders | 6 |
| Bore | 3.386–3.740" |
| Stroke | 3.161–3.378" |
| Compression | 10.2–11.7:1 |
| Advertised power | 250–464 hp |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| High Feature V6 · 3.740" × 3.378" · 11.5:1 | 222.7 ci | 3.7402" × 3.378" | 11.5:1 | 308–335 |
| High Feature V6 · 3.701" × 3.370" · 10.2:1 | 217 ci | 3.7008" × 3.3701" | 10.2:1 | 257–464 |
| LLT | 217 ci | 3.7008" × 3.3701" | 11.3:1 | 304 |
| LFX | 217 ci | 3.7008" × 3.3701" | 11.5:1 | 323 |
| High Feature V6 · 3.504" × 3.161" · 11.7:1 | 182 ci | 3.5039" × 3.1614" | 11.7:1 | 255–264 |
| LCV | 169 ci | 3.3858" × 3.1614" | 10.2:1 | 250 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
Compression spans 10.2:1 to 11.7:1, so fuel requirements differ meaningfully between members — worth checking before assuming parts interchange.
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.