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Chevrolet L88 specs: 427 ci 8-cylinder, 4.25 x 3.76 in (108 x 95.5 mm) bore and stroke, 12.5:1 compression. Rated 430 hp, 1967.
The Chevrolet 427ci (L88) is oversquare — the 4.25" bore exceeds the 3.76" stroke by 13.0% — a layout that favors airflow and RPM over leverage at the crank. The 3.76" stroke puts mean piston speed at 4,000 ft/min around 6,400 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.632 is in the range most production engines fall in. Each of the 8 cylinders displaces 53.4 ci (875 cc).
12.5:1 is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
It is one of 8 engines in the Chevrolet 427ci family, all of them 427 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 427 ci |
|---|---|
| Bore | 4.25" |
| Stroke | 3.76" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 12.5:1 |
| Rod length | 6.135" |
| Rod ratio | 1.632 |
| Bore/stroke ratio | 1.13 |
| Deck height | 9.8" |
| Fuel type | gas |
|---|---|
| Firing order | 1-8-4-3-6-5-7-2 |
| Advertised HP | 430 hp |
| Years | 1967 |
| Engine weight | 685 lb (approximate; published figures vary with what is attached) |
| Bore/stroke character | 1.130 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,760 ft/min — in the range typical of performance street engines |
| Rod ratio | 1.632 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 53.4 ci |
| Static compression | 12.5:1 — high enough that pump premium or better is normally required |
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1 factory vehicle, 1967–1969. Each year opens that model's engine table.