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Mercury FE (1966–1968) specs: 428 ci (7.0L) 8-cylinder, 4.13 x 3.984 in (104.9 x 101.2 mm) bore and stroke, 10.5:1 compression. Rated 345 hp, 1966–1968.
The Mercury FE (1966–1968) is close to square: 4.1299" bore against 3.9843" stroke, within 3.7%, which splits the difference between a high-revving layout and a torque layout. The 3.9843" stroke puts mean piston speed at 4,000 ft/min around 6,000 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.628 is in the range most production engines fall in. Each of the 8 cylinders displaces 53.5 ci (877 cc).
10.5:1 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 24 engines in the FE family, the largest at 428 ci. 3 factory variants share these dimensions, rated at 345 hp across 1966–1968.
| Displacement | 428 ci / 7 L |
|---|---|
| Bore | 4.1299" |
| Stroke | 3.9843" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 10.5:1 |
| Rod length | 6.488" |
| Rod ratio | 1.628 |
| Bore/stroke ratio | 1.037 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Firing order | 1-5-4-2-6-3-7-8 |
| Advertised HP | 345 hp |
| Years | 1966–1968 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. |
|---|---|---|---|---|
| 1966 | gross | 345 | — | 10.5:1 |
| 1967 | gross | 345 * | — | — |
Factory specification sheet. * Not yet cross-verified.
| Bore/stroke character | 1.037 — square — bore and stroke are within 5%, a balanced compromise |
|---|---|
| Mean piston speed at 6,000 RPM | 3,984 ft/min — in the range typical of performance street engines |
| Rod ratio | 1.628 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 53.5 ci |
| Static compression | 10.5:1 — in the range that usually runs on pump premium |
Each link opens the calculator with this engine's specs already filled in.
These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.
| Year | Advertised HP | Code |
|---|---|---|
| 1966 | 345 hp | — |
| 1967 | 345 hp | — |
| 1968 | — | — |
4 factory vehicles, 1966–1968. Each year opens that model's engine table.