Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 engine DIY maintenance and service manual

General Information

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 is an 454 in³ (7.44 L) internal combustion reciprocating V8 engine. It has bore/stroke ratio of 4.25 in × 4 in (10.8 cm × 10.16 cm), and uses 9:1 compression. This engine was rated 290 hp (216.25 kW) at 4200 rpm and 410 lbf⋅ft (555.89 N⋅m) of torque at 3200 rpm. It was used in Chevrolet, GMC, and Detroit Diesel cars.

Engine Performance Rating

SAE J1349 (SAE Net)

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 engine performance rating according to SAE J1349 (SAE Net) standard.
Parameter	Output
Power Rating	290 hp (216.25 kW) at 4200 RPM
Torque Rating	555.89 N⋅m410 lbf⋅ft410 lbf⋅ft at 3200 RPM

Specifications

General

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 engine general specifications.
Parameter	Value
Type	Internal Combustion Reciprocating
Fuel Type	Gasoline
Cylinder Configuration	V8
Engine Displacement	7.44 L454 in³454 in³
Bore	10.8 cm4.25 in4.25 in
Stroke	10.16 cm4 in4 in
Compression Ratio	9:1
Firing Order	1-8-4-3-6-5-7-2

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Block, crankshaft and pistons

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 engine block, crankshaft and pistons specifications.
Parameter	Value
Block Material	Cast Iron

Compression

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 engine compression.
Parameter	Value
Compression (minimal)	6.9 bar6.9 bar690 kPa
Compression (maximal difference)	70

Spark Plugs and Wires

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 spark plugs and wires specifications.
Parameter	Value
Spark Plug Gap	1.52 mm0.06 in0.06 in

Engine head and valvetrain

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 engine head and valvetrain specifications.
Parameter	Value
Valvetrain Type	OHV
Valves per Cylinder	2

Air Intake

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 air intake specifications.
Parameter	Value
Air Intake Method	Naturally Aspirated

Fuel Injection

Chevrolet gasoline Big-block Generation VI Vortec 7400 L21 fuel injection specifications.
Parameter	Value
Injection Type	Multi Point