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Oldsmobile 215 specs: 215 ci (3.5L) 8-cylinder, 3.50 x 2.799 in (88.9 x 71.1 mm) bore and stroke, 8.75:1 compression. Rated 155 hp. OHV.
The Oldsmobile Rockette (215) is oversquare — the 3.5" bore exceeds the 2.7992" stroke by 25.0% — a layout that favors airflow and RPM over leverage at the crank. The 2.7992" stroke does not reach 4,000 ft/min of mean piston speed until about 8,550 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 8 cylinders displaces 26.9 ci (440 cc).
8.75:1 on aluminum heads is low by modern standards and generally happy on regular pump fuel.
Factory fitments include the F-85, Cutlass, Jetfire.
| Displacement | 215 ci / 3.5 L |
|---|---|
| Bore | 3.5" |
| Stroke | 2.7992" |
| Cylinders | 8 |
| Compression ratio | 8.75:1 |
| Bore/stroke ratio | 1.25 |
| Block material | aluminum |
|---|---|
| Head material | aluminum |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 155 hp |
| Bore/stroke character | 1.250 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,799 ft/min — conservative for a street engine |
| Displacement per cylinder | 26.9 ci |
| Static compression | 8.75:1 — low by modern standards, generally happy on regular pump fuel |
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