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Buick LM1 (VIN L) specs: 350 ci (5.7L) 8-cylinder, 4.00 x 3.48 in (101.6 x 88.4 mm) bore and stroke, 8.5:1 compression. Rated 170 hp, 1977.
The Buick LM1 (VIN L) is oversquare — the 4" bore exceeds the 3.48" stroke by 14.9% — a layout that favors airflow and RPM over leverage at the crank. The 3.48" stroke puts mean piston speed at 4,000 ft/min around 6,900 RPM, which is where a production bottom end is generally considered at its limit. Each of the 8 cylinders displaces 43.8 ci (717 cc).
8.5:1 is low by modern standards and generally happy on regular pump fuel.
It is one of 11 engines in the Buick 350ci family, all of them 350 ci — the differences between them are in compression, heads and rating, not displacement.
| Displacement | 350 ci / 5.7 L |
|---|---|
| Bore | 4" |
| Stroke | 3.48" |
| Cylinders | 8 |
| Configuration | V8 |
| Compression ratio | 8.5:1 |
| Bore/stroke ratio | 1.149 |
How to tell which you have: The 5th character of the VIN is the engine code: L is the Chevrolet-built 350 4-bbl (LM1), the 170 hp engine in the 1977 Regal.
| Fuel type | gas |
|---|---|
| Firing order | 1-8-4-3-6-5-7-2 |
| Advertised HP | 170 hp |
| Years | 1977 |
| Year | Version | HP @ rpm | Torque @ rpm | Comp. | Duration int / exh | Valve lift int / exh | LSA |
|---|---|---|---|---|---|---|---|
| 1977 | LM1 net | 170 @ 3800 | 270 lb-ft @ 2400 | 8.5:1 | 280° / 288° | 0.390" / 0.410" | 113° |
Factory specification sheet. Durations are the factory's advertised figures at the basis printed on the sheet, not duration at .050" lift; lobe separation is calculated from the printed valve timing.
| Bore/stroke character | 1.149 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves |
|---|---|
| Mean piston speed at 6,000 RPM | 3,480 ft/min — conservative for a street engine |
| Displacement per cylinder | 43.8 ci |
| Static compression | 8.5:1 — low by modern standards, generally happy on regular pump fuel |
Each link opens the calculator with this engine's specs already filled in.
1 factory vehicle, 1977. Each year opens that model's engine table.