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Chevrolet RPO L63 specs: 164 ci (2.7L) 6-cylinder, 3.438 x 2.94 in (87.3 x 74.7 mm) bore and stroke, 9.25:1 compression. Rated 140 hp, 1967.
The Chevrolet RPO L63 is oversquare — the 3.438" bore exceeds the 2.94" stroke by 16.9% — a layout that favors airflow and RPM over leverage at the crank. The 2.94" stroke does not reach 4,000 ft/min of mean piston speed until about 8,150 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.605 is in the range most production engines fall in. Each of the 6 cylinders displaces 27.3 ci (448 cc).
9.25:1 is low by modern standards and generally happy on regular pump fuel.
It is one of 3 engines in the Chevrolet 164ci family, all of them 164 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 164 ci / 2.7 L |
|---|---|
| Bore | 3.438" |
| Stroke | 2.94" |
| Cylinders | 6 |
| Compression ratio | 9.25:1 * |
| Rod length | 4.72" |
| Rod ratio | 1.605 |
| Bore/stroke ratio | 1.169 |
* Compression ratio from a single source; not yet cross-verified.
| Fuel type | gas |
|---|---|
| Advertised HP | 140 hp |
| Years | 1967 |
| Bore/stroke character | 1.169 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 2,940 ft/min — conservative for a street engine |
| Rod ratio | 1.605 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 27.3 ci |
| Static compression | 9.25:1 — low by modern standards, generally happy on regular pump fuel |
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1 factory vehicle, 1965–1969. Each year opens that model's engine table.