Ford 351ci 9.4:1 Specs: 4.002 x 3.50 in, 156-300 hp

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Ford 351ci specs: 351 ci (5.8L) 8-cylinder, 4.002 x 3.50 in (101.7 x 88.9 mm) bore and stroke, 9.4:1 compression. Rated 156-300 hp, 1973–1995.

The Ford 351ci is oversquare — the 4.002" bore exceeds the 3.5" stroke by 14.3% — a layout that favors airflow and RPM over leverage at the crank. The 3.5" stroke puts mean piston speed at 4,000 ft/min around 6,850 RPM, which is where a production bottom end is generally considered at its limit. A rod ratio of 1.651 is in the range most production engines fall in. Each of the 8 cylinders displaces 43.9 ci (719 cc).

9.4:1 on iron heads is low by modern standards and generally happy on regular pump fuel.

It is one of 37 engines in the Ford 351ci family, all of them 351 ci — the differences between them are in compression, heads and rating, not displacement. 3 factory variants share these dimensions, rated from 156 to 300 hp across 1973–1995.

Dimensions

Displacement351 ci / 5.8 L
Bore4.002"
Stroke3.5"
Cylinders8
ConfigurationV8
Compression ratio9.4:1
Rod length5.78"
Rod ratio1.651
Bore/stroke ratio1.143

Construction

Block materialcast iron
Head materialcast iron
ValvetrainOHV
Fuel typegas
Advertised HP156–300 hp
Years1973–1995

What these numbers mean

Bore/stroke character1.143 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves
Mean piston speed at 6,000 RPM3,500 ft/min — conservative for a street engine
Rod ratio1.651 — moderate — the range most production V8s fall in
Displacement per cylinder43.9 ci
Static compression9.4:1 — low by modern standards, generally happy on regular pump fuel

Cylinder head

Intake valve diameter1.852"
Exhaust valve diameter1.55"

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Variants sharing these dimensions (3)

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

YearAdvertised HPCode
1973156 hp—
1973158 hp—
1995300 hp—

Factory cars with this engine

Similar engines

← All Ford 351ci engines