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Pontiac 250 Ohc6 Sprint specs: 250 ci (4.1L) 6-cylinder, 3.874 x 3.531 in (98.4 x 89.7 mm) bore and stroke, 10.5:1 compression. Rated 215 hp. SOHC.
The Pontiac 250 Ohc6 Sprint is oversquare — the 3.874" bore exceeds the 3.5315" stroke by 9.7% — a layout that favors airflow and RPM over leverage at the crank. The 3.5315" stroke puts mean piston speed at 4,000 ft/min around 6,800 RPM, which is where a production bottom end is generally considered at its limit. Each of the 6 cylinders displaces 41.7 ci (683 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 4 engines in the Pontiac OHC-6 family, the largest at 250 ci. Factory fitments include the Pontiac Firebird Sprint, Pontiac LeMans, Pontiac LeMans Sprint.
| Displacement | 250 ci / 4.1 L |
|---|---|
| Bore | 3.874" |
| Stroke | 3.5315" |
| Cylinders | 6 |
| Compression ratio | 10.5:1 |
| Bore/stroke ratio | 1.097 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | SOHC |
| Fuel type | gas |
| Advertised HP | 215 hp |
| Bore/stroke character | 1.097 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,532 ft/min — in the range typical of performance street engines |
| Displacement per cylinder | 41.7 ci |
| Static compression | 10.5:1 — in the range that usually runs on pump premium |
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