Buick Small-Block V8 3.800" bore Specs: 3.80 x 3.85 in, 140-165 hp

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Buick Small-Block V8 3.800" bore specs: 350 ci (5.7L) 8-cylinder, 3.80 x 3.85 in (96.5 x 97.8 mm) bore and stroke. Rated 140-165 hp, 1975–1978.

The Buick Small-Block V8 3.800" bore is close to square: 3.8" bore against 3.85" stroke, within 1.3%, which splits the difference between a high-revving layout and a torque layout. The 3.85" stroke puts mean piston speed at 4,000 ft/min around 6,250 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).

It is one of 8 engines in the Buick Small-Block V8 family, the largest at 350 ci. 7 factory variants share these dimensions, rated from 140 to 165 hp across 1975–1978. Factory fitments include the Buick Skylark, Buick LeSabre, Buick Riviera and 6 others.

Dimensions

Displacement350 ci / 5.7 L
Bore3.8"
Stroke3.85"
Cylinders8
Bore/stroke ratio0.987

Construction

Block materialcast iron
ValvetrainOHV
Fuel typegas
Advertised HP140–165 hp
Years1975–1978

What these numbers mean

Bore/stroke character0.987 — square — bore and stroke are within 5%, a balanced compromise
Mean piston speed at 6,000 RPM3,850 ft/min — in the range typical of performance street engines
Displacement per cylinder43.8 ci

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Variants sharing these dimensions (7)

These records share identical bore, stroke, displacement and compression. They differ by model year and factory power rating.

YearAdvertised HPCode
1975145 hp350-2
1975165 hp350-4
1976140 hp350-2
1976155 hp350-4
1977140 hpL32
1977155 hpL77
1978155 hpL77

Factory cars with this engine

Vehicles (9)

Similar engines

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