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Chevrolet 402ci (1970) specs: 402 ci (6.6L) 8-cylinder, 4.125 x 3.766 in (104.8 x 95.7 mm) bore and stroke. Rated 310 hp, 1970.
The Chevrolet 402ci (1970) is oversquare — the 4.125" bore exceeds the 3.766" stroke by 9.5% — a layout that favors airflow and RPM over leverage at the crank. The 3.766" stroke puts mean piston speed at 4,000 ft/min around 6,350 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.629 is in the range most production engines fall in. Each of the 8 cylinders displaces 50.3 ci (823 cc).
It is one of 8 engines in the Chevrolet 402ci family, all of them 402 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 402 ci / 6.6 L |
|---|---|
| Bore | 4.125" |
| Stroke | 3.766" |
| Cylinders | 8 |
| Configuration | V8 |
| Rod length | 6.136" |
| Rod ratio | 1.629 |
| Bore/stroke ratio | 1.095 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 310 hp |
| Years | 1970 |
| Bore/stroke character | 1.095 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,766 ft/min — in the range typical of performance street engines |
| Rod ratio | 1.629 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 50.3 ci |
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