Chevrolet gasoline Big-block Mark IV 396 CID (6.5 L) and 402 CID (6.6 L) 402 LS3 300 hp engine DIY maintenance and service manual

General Information

Chevrolet gasoline Big-block Mark IV 396 CID (6.5 L) and 402 CID (6.6 L) 402 LS3 300 hp is an 402 in³ (6.59 L) internal combustion reciprocating V8 engine. It has bore/stroke ratio of 4.124 in × 3.76 in (10.475 cm × 9.55 cm), and uses 8.5:1 compression. This engine was rated 300 hp (223.71 kW) at 4800 rpm and 400 lbf⋅ft (542.33 N⋅m) of torque at 3200 rpm. It was used in Chevrolet cars.

Produced 1971, hydraulic lifters, nodular iron crankshaft, and two-bolt main caps.

Engine Performance Rating

SAE J1349 (SAE Net)

Chevrolet gasoline Big-block Mark IV 396 CID (6.5 L) and 402 CID (6.6 L) 402 LS3 300 hp engine performance rating according to SAE J1349 (SAE Net) standard.
Parameter	Output
Power Rating	300 hp (223.71 kW) at 4800 RPM
Torque Rating	542.33 N⋅m400 lbf⋅ft400 lbf⋅ft at 3200 RPM

Specifications

General

Chevrolet gasoline Big-block Mark IV 396 CID (6.5 L) and 402 CID (6.6 L) 402 LS3 300 hp engine general specifications.
Parameter	Value
Type	Internal Combustion Reciprocating
Fuel Type	Gasoline
Cylinder Configuration	V8
Engine Displacement	6.59 L402 in³402 in³
Bore	10.475 cm4.124 in4.124 in
Stroke	9.55 cm3.76 in3.76 in
Compression Ratio	8.5:1

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Block, crankshaft and pistons

Chevrolet gasoline Big-block Mark IV 396 CID (6.5 L) and 402 CID (6.6 L) 402 LS3 300 hp engine block, crankshaft and pistons specifications.
Parameter	Value
Block Material	Cast Iron

Engine head and valvetrain

Chevrolet gasoline Big-block Mark IV 396 CID (6.5 L) and 402 CID (6.6 L) 402 LS3 300 hp engine head and valvetrain specifications.
Parameter	Value
Valvetrain Type	OHV
Valves per Cylinder	2

Fuel Injection

Chevrolet gasoline Big-block Mark IV 396 CID (6.5 L) and 402 CID (6.6 L) 402 LS3 300 hp fuel injection specifications.
Parameter	Value
Injection Type	Carburetor