TorqueList Technical Reference
One Twenty Straight-Eight
Packard 257 One Twenty Straight-Eight
The compact 1935 Packard Eight that brought modern independent front suspension and a lighter engine package to the new One Twenty.
257
Cubic inches
TorqueList Original Technical Art
Packard 257 One Twenty Straight-Eight
Inline8 · N/A
Why it matters
Key takeaway
The 257 helped launch Packard's lower-priced One Twenty line and showed the company could build a smaller, lighter straight-eight without abandoning Packard smoothness.
Key variants
Engineering
Technical specification
- Architecture
- L-head inline eight
- Block
- Cast iron
- Cylinder heads
- Cast iron
- Valvetrain
- Side-valve L-head
- Aspiration
- Naturally aspirated
- Fuel delivery
- Carbureted
- Firing order
- 1-6-2-5-8-3-7-4
- Main bearings
- 5
The 257 was a relatively compact Packard L-head straight-eight created for the new One Twenty line. Its 3.25-inch bore and 3.875-inch stroke, 6.5:1 compression, and five-main-bearing support balanced traditional Packard smoothness with a lighter, more affordable package.
Builder reference
Internal Specifications
Variant-specific values are labeled. For engine families with multiple factory combinations, the exact RPO/code/year takes priority over the family summary.
Identification & Output
- Engine codes / RPO
- 1935 One Twenty motor-number/vehicle-series identification; no modern RPO-style engine code
- Casting numbers
- No single universal 257 block/head casting is retained here; identify by Packard motor number, 3.25 x 3.875-inch bore/stroke, model year and One Twenty application.
- Power rating
- Period brake horsepower / SAE gross-era rating
- Horsepower RPM
- 110 hp @ 3850 rpm
- Torque RPM
- 203 lb-ft @ 2000 rpm
Operating Specs
- Production notes
- Introduced with the One Twenty for 1935, the 257 used a 3.25-inch bore and 3.875-inch stroke, 6.5:1 compression and a single carburetor. It was enlarged to 282 cid for 1936.
Compatibility Notes
- The 257 is the one-year first-generation One Twenty straight-eight; do not assume later 282 internals are identical despite the shared 3.25-inch bore.
- Use Packard motor number, bore/stroke and year-specific external hardware to identify a loose engine before ordering pistons, gaskets, ignition or clutch parts.
Factory fitment
Notable applications
Versions that matter
Key factory / build variants
1935 One Twenty 257
First engine of Packard’s volume-market One Twenty line
1935
110 hp @ 3850 rpm; 203 lb-ft @ 2000 rpm
Strengths
- Compact by Packard standards
- Five-main-bearing crank support
- Strong period torque
Watch-outs
- One-year displacement
- Flathead breathing limits performance
- Original components are restoration-focused
Common upgrades
- Period-correct carburetor rebuild
- Electronic ignition hidden in stock distributor
- Cooling-system restoration
Builder notes
Engineering notes worth knowing
3.25 x 3.875-inch bore and stroke; 257 cu in / 4.2 L.
L-head straight-eight with cast-iron block and head.
Factory output: 110 hp with about 203 lb-ft at 2,000 rpm.
Used for the 1935 Packard One Twenty.
History & context
The story behind the engine
The One Twenty changed Packard’s business by bringing the brand into a lower price class without abandoning the smooth straight-eight character buyers expected. Its one-year 257 engine was the first step in that strategy.
Racing history
The 257 was developed for the new One Twenty’s combination of refinement, lighter weight and everyday performance rather than a factory racing program. Its importance is commercial and engineering: it powered the car that broadened Packard’s market during the Depression.
Legacy
The 257 was the short-lived first step toward the better-known 282 One Twenty engine.
Verification
Reference sources
Packard Club 1935 One Twenty reference data
club reference
Packard bore/stroke reference
technical reference
Packard straight-eight firing-order reference
technical reference
1935 Packard One Twenty specifications
historical specification
Packard Club — year/model/motor-number identification reference
club identification reference
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