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Chrysler 354ci (2021) · 630 hp specs: 354 ci (5.8L) 8-cylinder, 4.07 x 3.40 in (103.4 x 86.4 mm) bore and stroke, 12.5:1 compression. Rated 630 hp, 2021. OHV.
The Chrysler 354ci (2021) · 630 hp is oversquare — the 4.07" bore exceeds the 3.4" stroke by 19.7% — a layout that favors airflow and RPM over leverage at the crank. The 3.4" stroke does not reach 4,000 ft/min of mean piston speed until about 7,050 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.853 is long by production standards — less side-load on the cylinder wall and gentler piston acceleration around TDC, the geometry that tolerates high RPM. Each of the 8 cylinders displaces 44.3 ci (725 cc).
12.5:1 on iron heads is high for a production gasoline engine; running a ratio like that on pump fuel depends on chamber design and fuel delivery rather than the number alone.
| Displacement | 354 ci / 5.8 L |
|---|---|
| Bore | 4.07" |
| Stroke | 3.4" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 12.5:1 |
| Rod length | 6.3" |
| Rod ratio | 1.853 |
| Bore/stroke ratio | 1.197 |
| Piston deck clearance | 0" |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 630 hp |
| Years | 2021 |
| Bore/stroke character | 1.197 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,400 ft/min — conservative for a street engine |
| Rod ratio | 1.853 — long — less side loading on the cylinder wall, favours high RPM |
| Displacement per cylinder | 44.3 ci |
| Static compression | 12.5:1 — high enough that pump premium or better is normally required |
| Intake valve diameter | 2.2" |
|---|---|
| Exhaust valve diameter | 1.68" |
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