Bore, stroke, displacement and compression for all 3 Pontiac 215ci engines, compared side by side. Plus rod ratio and head specs where published.
| Displacement | 215 ci |
|---|---|
| Cylinders | 6, 8 |
| Bore | 3.500–3.750" |
| Stroke | 2.800–3.250" |
| Compression | 8.6–10.3:1 |
| Advertised power | 140–185 hp |
| Years | 1961–1965 |
| Cylinder head data | 3 of 3 engines |
| Engine | Displacement | Bore × Stroke | CR | HP |
|---|---|---|---|---|
| Pontiac 215ci · 3.5" × 2.8" · 8.8:1 | 215 ci | 3.5" × 2.8" | 8.8:1 | 155 |
| Pontiac 215ci · 3.5" × 2.8" · 10.25:1 | 215 ci | 3.5" × 2.8" | 10.25:1 | 185 |
| Pontiac 215ci · 3.75" × 3.25" · 8.6:1 | 215 ci | 3.75" × 3.25" | 8.6:1 | 140 |
Both bore and stroke vary across the family, so these are separate castings rather than variations on one block.
Compression spans 8.6:1 to 10.25:1, 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.