GMC 250 Specs

GMC 250 engine specs: 250 ci (4.1L), 6-cylinder, 3.875" bore x 3.53" stroke, 8.5:1 compression.

Dimensions

Displacement	250 ci / 4.1 L
Bore	3.875"
Stroke	3.53"
Cylinders	6
Compression ratio	8.5:1
Bore/stroke ratio	1.098

Construction

Block material	cast iron
Head material	cast iron
Valvetrain	OHV
Fuel type	gas
Advertised HP	155 hp

What these numbers mean

Bore/stroke character	1.098 — oversquare — bore exceeds stroke, which favours higher RPM and larger valves
Mean piston speed at 6,000 RPM	3,530 ft/min — in the range typical of performance street engines
Displacement per cylinder	41.7 ci
Static compression	8.5:1 — low by modern standards, generally happy on regular pump fuel

Run the numbers for this engine

Each link opens the calculator with this engine's specs already filled in.

• Displacement calculator
• Compression ratio calculator
• Piston ring gap calculator
• Piston speed calculator
• Carburetor CFM calculator

Vehicles (5)

• Chevrolet Chevelle
• Chevrolet Camaro
• Chevrolet Nova
• Chevrolet C/K Series
• Pontiac Firebird

Similar engines

• GMC 230 — 230 ci
• GMC 292 — 292 ci
• GMC 194 — 194 ci
• GMC LL8 — 256 ci
• GMC 261 — 261 ci
• GMC Vortec 4300 (4.3L V6) · 4.000" × 3.480" · 9.2:1 — 262 ci
• Cadillac V8 — 250 ci
• Chevrolet Chevrolet 250ci · 3.875" × 3.530" · 8.801:1 — 250 ci

← All Chevy Straight-6 (194/230/250/292) engines