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Dodge 426ci (1963–1970) specs: 426 ci (7.0L) 8-cylinder, 4.25 x 3.75 in (108 x 95.3 mm) bore and stroke. Rated 365-425 hp, 1963–1970.
The Dodge 426ci (1963–1970) is oversquare — the 4.25" bore exceeds the 3.75" stroke by 13.3% — a layout that favors airflow and RPM over leverage at the crank. The 3.75" stroke puts mean piston speed at 4,000 ft/min around 6,400 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 53.3 ci (873 cc).
It is one of 7 engines in the Dodge 426ci family, all of them 426 ci — the differences between them are in compression, heads and rating, not displacement. 10 factory variants share these dimensions, rated from 365 to 425 hp across 1963–1970.
| Displacement | 426 ci / 7 L |
|---|---|
| Bore | 4.25" |
| Stroke | 3.75" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 10.25–11:1 (published figures vary) |
| Bore/stroke ratio | 1.133 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Firing order | 1-8-4-3-6-5-7-2 |
| Advertised HP | 365–425 hp |
| Years | 1963–1970 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. | Duration int / exh | Valve lift int / exh | LSA |
|---|---|---|---|---|---|---|---|
| 1963 | gross | 415 @ 5600 | 470 lb-ft @ 4400 | 11:1 | — | — | — |
| 1964 | gross | 365 @ 4800 | 470 lb-ft @ 3200 | 10.3:1 | — | — | — |
| 1964 | gross | 415 @ 5600 | 470 lb-ft @ 4400 | 11:1 | — | — | — |
| 1965 | gross | 365 @ 4800 | 470 lb-ft @ 3200 | 10.3:1 | 268° | 0.430" | 110° |
| 1967 | gross | 425 @ 5000 | 490 lb-ft @ 4000 | 10.25:1 | 276° | 0.467" / 0.473" | 112° |
| 1968 | gross | 425 @ 5000 | 490 lb-ft @ 4000 | 10.25:1 | 284° | 0.467" / 0.473" | 112° |
| 1969 | gross | 425 @ 5000 | 490 lb-ft @ 4000 | 10.25:1 | — | — | — |
Factory specification sheet. Durations are the factory's advertised figures at the basis printed on the sheet, not duration at .050" lift; lobe separation is calculated from the printed valve timing.
| Bore/stroke character | 1.133 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,750 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 53.3 ci |
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 |
|---|---|---|
| 1963 | 415 hp | — |
| 1963 | 425 hp | — |
| 1964 | 365 hp | — |
| 1964 | 415 hp | — |
| 1964 | 425 hp | — |
| 1965 | 365 hp | — |
| 1967 | 425 hp | — |
| 1968 | 425 hp | — |
| 1969 | 425 hp | — |
| 1970 | 425 hp | — |
4 factory vehicles, 1963–1965. Each year opens that model's engine table.