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Ford 1973 200 84HP specs: 200 ci (3.3L) 6-cylinder, 3.684 x 3.126 in (93.6 x 79.4 mm) bore and stroke, 9.38:1 compression. Rated 84 hp, 1973.
The Ford 1973 200 84HP is oversquare — the 3.684" bore exceeds the 3.126" stroke by 17.9% — a layout that favors airflow and RPM over leverage at the crank. The 3.126" stroke does not reach 4,000 ft/min of mean piston speed until about 7,700 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. A rod ratio of 1.508 is short — higher piston acceleration and more side-load, typical of stroker combinations and a reason to watch piston speed closely. Each of the 6 cylinders displaces 33.3 ci (546 cc).
9.38:1 on iron heads is low by modern standards and generally happy on regular pump fuel.
It is one of 9 engines in the Ford 200ci family, all of them 200 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 200 ci / 3.3 L |
|---|---|
| Bore | 3.684" |
| Stroke | 3.126" |
| Cylinders | 6 |
| Configuration | I6 |
| Compression ratio | 9.38:1 |
| Rod length | 4.715" |
| Rod ratio | 1.508 |
| Bore/stroke ratio | 1.179 |
| Piston deck clearance | 0.012" |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | OHV |
| Fuel type | gas |
| Advertised HP | 84 hp |
| Years | 1973 |
| Bore/stroke character | 1.179 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,126 ft/min — conservative for a street engine |
| Rod ratio | 1.508 — short — more side loading and piston dwell at TDC, typical of stroker combinations |
| Displacement per cylinder | 33.3 ci |
| Static compression | 9.38:1 — low by modern standards, generally happy on regular pump fuel |
| Intake valve diameter | 1.66" |
|---|---|
| Exhaust valve diameter | 1.399" |
| Chamber volume | 48.32 cc |
| Rocker ratio | 1.5:1 |
| Lifter type | hydraulic |
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