Ford 351ci (1970) Specs: 4.002 x 3.50 in, 250-300 hp

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Ford 351ci (1970) specs: 351 ci (5.8L) 8-cylinder, 4.002 x 3.50 in (101.7 x 88.9 mm) bore and stroke. Rated 250-300 hp, 1970. OHV. Rod ratio and piston speed.

The Ford 351ci (1970) 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).

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. 2 factory variants share these dimensions, rated from 250 to 300 hp in 1970.

Dimensions

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

Construction

Block materialcast iron
Head materialcast iron
ValvetrainOHV
Fuel typegas
Advertised HP250–300 hp
Years1970

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

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Variants sharing these dimensions (2)

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

YearAdvertised HPCode
1970250 hp—
1970300 hp—

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