Plymouth J Specs

Plymouth J engine specs: 340 ci (5.6L), 8-cylinder, 4.0315" bore x 3.311" stroke, 10.5:1 compression.

Dimensions

Displacement340 ci / 5.6 L
Bore4.0315"
Stroke3.311"
Cylinders8
Compression ratio10.5:1
Bore/stroke ratio1.218

Construction

Block materialcast iron
Head materialcast iron
ValvetrainOHV
Fuel typegas
Advertised HP275–290 hp

What these numbers mean

Bore/stroke character1.218 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves
Mean piston speed at 6,000 RPM3,311 ft/min — conservative for a street engine
Displacement per cylinder42.5 ci
Static compression10.5:1 — in the range that usually runs on pump premium

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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
275 hpJ
290 hpJ

Vehicles (5)

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