GMC 6V71 Specs

GMC 6V71 engine specs: 426 ci (7L), 6-cylinder, 4.252" bore x 4.4882" stroke, 18.7:1 compression.

Dimensions

Displacement	426 ci / 7 L
Bore	4.252"
Stroke	4.4882"
Cylinders	6
Compression ratio	18.7:1
Bore/stroke ratio	0.947

Construction

Block material	cast iron
Head material	cast iron
Valvetrain	OHV
Fuel type	diesel
Advertised HP	230 hp

What these numbers mean

Bore/stroke character	0.947 — undersquare — stroke exceeds bore, which favours low-end torque
Mean piston speed at 6,000 RPM	4,488 ft/min — in the range typical of performance street engines
Displacement per cylinder	71.0 ci
Static compression	18.7:1 — high enough that pump premium or better is normally required

Run the numbers for this engine

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• Displacement calculator
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• Carburetor CFM calculator

Vehicles (5)

• GMC Astro
• GMC General
• Various transit buses
• Marine applications
• Industrial applications

Similar engines

• GMC 8V53 — 424 ci
• GMC 6V53 — 318 ci
• GMC 8V71 — 568 ci
• GMC 8V92 — 736 ci
• GMC 6-71 — 426 ci
• GMC 427 — 427 ci
• Chrysler Chrysler 426ci · 4.125" × 4.000" · 14.9:1 — 426 ci
• Plymouth R — 426 ci

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