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Mercury 385 460 specs: 460 ci (7.5L) 8-cylinder, 4.36 x 3.85 in (110.7 x 97.8 mm) bore and stroke. Rated 197-218 hp, 1975–1978.
The Mercury 385 460 is oversquare — the 4.36" bore exceeds the 3.85" stroke by 13.2% — a layout that favors airflow and RPM over leverage at the crank. The 3.85" stroke puts mean piston speed at 4,000 ft/min around 6,250 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 57.5 ci (942 cc).
It is one of 10 engines in the 385 family, the largest at 460 ci. 4 factory variants share these dimensions, rated from 197 to 218 hp across 1975–1978.
| Displacement | 460 ci / 7.5 L |
|---|---|
| Bore | 4.36" |
| Stroke | 3.85" |
| Cylinders | 8 |
| Configuration | V8 |
| Bore/stroke ratio | 1.132 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 197–218 hp |
| Years | 1975–1978 |
| Bore/stroke character | 1.132 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,850 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 57.5 ci |
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These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1975 | 218 hp | 385 460 |
| 1976 | 202 hp | 385 460 |
| 1977 | 197 hp | 385 460 |
| 1978 | 202 hp | 385 460 |