Chevrolet 396ci 10.25:1 Specs: 4.094 x 3.766 in, 325-360 hp

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Chevrolet 396ci specs: 396 ci (6.5L) 8-cylinder, 4.094 x 3.766 in (104 x 95.7 mm) bore and stroke, 10.25:1 compression. Rated 325-360 hp, 1966–1969.

The Chevrolet 396ci is oversquare — the 4.094" bore exceeds the 3.766" stroke by 8.7% — a layout that favors airflow and RPM over leverage at the crank. The 3.766" stroke puts mean piston speed at 4,000 ft/min around 6,350 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.629 is in the range most production engines fall in. Each of the 8 cylinders displaces 49.5 ci (811 cc).

10.25:1 is in the range that usually runs on pump premium.

It is one of 6 engines in the Chevrolet 396ci family, all of them 396 ci — the differences between them are in compression, heads and rating, not displacement. 8 factory variants share these dimensions, rated from 325 to 360 hp across 1966–1969.

Dimensions

Displacement396 ci / 6.5 L
Bore4.094"
Stroke3.766"
Cylinders8
Compression ratio10.25:1
Rod length6.136"
Rod ratio1.629
Bore/stroke ratio1.087
Piston deck clearance0.008"

Construction

Induction1-4
Advertised HP325–360 hp
Years1966–1969

What these numbers mean

Bore/stroke character1.087 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves
Mean piston speed at 6,000 RPM3,766 ft/min — in the range typical of performance street engines
Rod ratio1.629 — moderate — the range most production V8s fall in
Displacement per cylinder49.5 ci
Static compression10.25:1 — in the range that usually runs on pump premium

Cylinder head

Intake valve diameter2.07"
Exhaust valve diameter1.725"
Chamber volume96.4 cc
Rocker ratio1.7:1
Lifter typehydraulic

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Variants sharing these dimensions (8)

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

YearAdvertised HPCode
1966325 hp—
1966360 hp—
1967325 hp—
1967350 hp—
1968325 hp—
1968350 hp—
1969325 hp—
1969350 hp—

Factory cars with this engine

Similar engines

← All Chevrolet 396ci engines