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Buick 430 specs: 430 ci (7.0L) 8-cylinder, 4.188 x 3.90 in (106.4 x 99.1 mm) bore and stroke, 10.25:1 compression. Rated 360 hp. Rod ratio and piston speed.
The Buick Big-Block V8 (430) is oversquare — the 4.1875" bore exceeds the 3.9" stroke by 7.4% — a layout that favors airflow and RPM over leverage at the crank. The 3.9" stroke puts mean piston speed at 4,000 ft/min around 6,150 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 53.8 ci (881 cc).
10.25:1 on iron heads is in the range that usually runs on pump premium; iron holds heat, so treat it as the less forgiving side of that range.
It is one of 3 engines in the Buick Big-Block V8 family, sitting between the 400 ci and 455 ci members. Factory fitments include the Buick Electra, Buick Wildcat, Buick Riviera and 5 others.
| Displacement | 430 ci / 7 L |
|---|---|
| Bore | 4.1875" |
| Stroke | 3.9" |
| Cylinders | 8 |
| Compression ratio | 10.25:1 |
| Bore/stroke ratio | 1.074 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 360 hp |
| Bore/stroke character | 1.074 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,900 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 53.8 ci |
| Static compression | 10.25:1 — in the range that usually runs on pump premium |
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