Buick Small-Block V8 9:1 Specs: 3.80 x 3.85 in, 230-285 hp

See other engines in this family

Buick Small-Block V8 specs: 350 ci (5.7L) 8-cylinder, 3.80 x 3.85 in (96.5 x 97.8 mm) bore and stroke, 9:1 compression. Rated 230-285 hp, 1968–1970.

The Buick Small-Block V8 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).

9:1 is low by modern standards and generally happy on regular pump fuel.

It is one of 8 engines in the Buick Small-Block V8 family, the largest at 350 ci. 4 factory variants share these dimensions, rated from 230 to 285 hp across 1968–1970. Factory fitments include the Buick Skylark, Buick LeSabre, Buick Riviera and 6 others.

Dimensions

Displacement350 ci / 5.7 L
Bore3.8"
Stroke3.85"
Cylinders8
Compression ratio9:1
Bore/stroke ratio0.987

Construction

Block materialcast iron
ValvetrainOHV
Fuel typegas
Advertised HP230–285 hp
Years1968–1970

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
Static compression9:1 — low by modern standards, generally happy on regular pump fuel

Run the numbers for this engine

Each link opens the calculator with this engine's specs already filled in.

Variants sharing these dimensions (4)

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

YearAdvertised HPCode
1968230 hp350-2
1969230 hp350-2
1970260 hp350-2
1970285 hp350-4

Factory cars with this engine

Vehicles (9)

Similar engines

← All Buick Small-Block V8 engines