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Ford R-code specs: 428 ci (7.0L) 8-cylinder, 4.132 x 3.984 in (105 x 101.2 mm) bore and stroke. Built 1968. Used in the Ford Ranchero.
The Ford R-code is close to square: 4.132" bore against 3.984" stroke, within 3.7%, which splits the difference between a high-revving layout and a torque layout. The 3.984" 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 1.629 is in the range most production engines fall in. Each of the 8 cylinders displaces 53.5 ci (877 cc).
It is one of 7 engines in the Ford 428ci family, all of them 428 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 428 ci / 7 L |
|---|---|
| Bore | 4.132" |
| Stroke | 3.984" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 10.6–11:1 (published figures vary) |
| Rod length | 6.488" |
| Rod ratio | 1.629 |
| Bore/stroke ratio | 1.037 |
| Deck height | 10.17" |
| Fuel type | gas |
|---|---|
| Firing order | 1-5-4-2-6-3-7-8 |
| Years | 1968 |
| 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 | 1.629 — moderate — the range most production V8s fall in |
| Displacement per cylinder | 53.5 ci |
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1 factory vehicle, 1968. Each year opens that model's engine table.