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Pontiac OHC-6 specs: 230 ci (3.8L) 6-cylinder, 3.874 x 3.252 in (98.4 x 82.6 mm) bore and stroke, 9:1 compression. Rated 160-165 hp. SOHC.
The Pontiac OHC-6 is oversquare — the 3.874" bore exceeds the 3.252" stroke by 19.1% — a layout that favors airflow and RPM over leverage at the crank. The 3.252" stroke does not reach 4,000 ft/min of mean piston speed until about 7,400 RPM, so piston speed is not what limits this engine's revs — valvetrain and breathing are. Each of the 6 cylinders displaces 38.3 ci (628 cc).
9:1 on iron heads is low by modern standards and generally happy on regular pump fuel.
It is one of 4 engines in the Pontiac OHC-6 family, the smallest at 230 ci. 4 factory variants share these dimensions, rated from 160 to 165 hp. Factory fitments include the Pontiac Tempest, Pontiac LeMans, Pontiac Firebird and 3 others.
| Displacement | 230 ci / 3.8 L |
|---|---|
| Bore | 3.874" |
| Stroke | 3.252" |
| Cylinders | 6 |
| Compression ratio | 9:1 |
| Bore/stroke ratio | 1.191 |
| Block material | cast iron |
|---|---|
| Head material | cast iron |
| Valvetrain | SOHC |
| Fuel type | gas |
| Advertised HP | 160–165 hp |
| Bore/stroke character | 1.191 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,252 ft/min — conservative for a street engine |
| Displacement per cylinder | 38.3 ci |
| Static compression | 9:1 — low by modern standards, generally happy on regular pump fuel |
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 |
|---|---|---|
| — | 160 hp | 230 |
| — | 165 hp | 230 OHC-6 |
| — | 165 hp | OHC-6 |
| — | 165 hp | 230, 230 OHC, 230 OHC-6, OHC-6, OHC-6 (1-barrel) |