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Buick Small-Block V8 (1971–1975) specs: 350 ci (5.7L) 8-cylinder, 3.80 x 3.85 in (96.5 x 97.8 mm) bore and stroke, 8.5:1 compression. Rated 150-260 hp.
The Buick Small-Block V8 (1971–1975) is close to square: 3.8" bore against 3.85" stroke, within 1.3%, which splits the difference between a high-revving layout and a torque layout. The 3.85" stroke puts mean piston speed at 4,000 ft/min around 6,250 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 43.8 ci (717 cc).
8.5:1 is low by modern standards and generally happy on regular pump fuel.
It is one of 7 engines in the Buick Small-Block V8 family, the largest at 350 ci. 9 factory variants share these dimensions, rated from 150 to 260 hp across 1971–1975.
| Displacement | 350 ci / 5.7 L |
|---|---|
| Bore | 3.8" |
| Stroke | 3.85" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 8.5:1 |
| Bore/stroke ratio | 0.987 |
| Block material | cast iron |
|---|---|
| Valvetrain | OHV |
| Fuel type | gas |
| Firing order | 1-8-4-3-6-5-7-2 |
| Advertised HP | 150–260 hp |
| Years | 1971–1975 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 1974 | 350-2 net | 150 @ 3600 | 270 lb-ft @ 2000 | 8.5:1 |
| 1974 | 350-4 net | 175 @ 3800 | 260 lb-ft @ 2000 | 8.5:1 |
Factory specification sheet.
| Bore/stroke character | 0.987 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,850 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 43.8 ci |
| Static compression | 8.5:1 — low by modern standards, generally happy on regular pump fuel |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1971 | — | — |
| 1971 | 260 hp | — |
| 1972 | — | — |
| 1972 | 155 hp | — |
| 1972 | 180 hp | — |
| 1972 | 195 hp | — |
| 1974 | 150 hp | — |
| 1974 | 175 hp | — |
| 1975 | — | — |
3 factory vehicles, 1971–1975. Each year opens that model's engine table.