American Autowire - 1970-1972 Engine Wire Harness-GM Truck - 31520H
$189.05
DESCRIPTION
American Autowire - 1970-1972 Engine Wire Harness-GM Truck - 31520H
Replace aging engine wiring and accommodate an HEI ignition conversion with this 1970–1972 Chevrolet V8 Engine Wiring Harness from American Autowire.
Designed for 1970–1972 Chevrolet trucks equipped with a V8 engine and automatic transmission, this Factory Fit replacement harness features wiring modified for a GM large-cap HEI distributor.
Unlike an original points-ignition harness, this HEI version replaces the factory ignition resistance wire with a standard 12-volt feed. It also includes a connector for a GM large-cap HEI distributor.
American Autowire manufactures its Factory Fit engine harnesses according to original General Motors specifications. Each harness arrives fully assembled and taped, connects at the factory firewall location, and follows original-style routing through the engine compartment.
Whether you're restoring a classic Chevy C10, replacing deteriorated wiring, or upgrading your V8-powered truck to electronic ignition, this harness provides an application-specific replacement for your truck's electrical configuration.
Manufacturer: American Autowire
Manufacturer Part Number: 31520H
Product Type: Engine Wiring Harness
Product Line: Factory Fit
Vehicle Years: 1970–1972
Vehicle Application: Chevrolet Trucks
Engine Application: V8
Transmission: Automatic
Ignition Configuration: HEI Electronic Ignition
Ignition Feed: Standard 12-Volt Feed
Distributor Connector: GM Large-Cap HEI
Quantity: Sold Individually
Features
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Designed for 1970–1972 Chevrolet truck applications
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Intended for V8 engines with automatic transmissions
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Modified for HEI electronic ignition
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Replaces the original ignition resistance wire with a standard 12-volt feed
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Includes a connector for a GM large-cap HEI distributor
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Manufactured by American Autowire
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Part of the Factory Fit replacement wiring line
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Manufactured according to original GM specifications
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Fully assembled and taped
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Connects at the original firewall location
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Follows factory-style engine compartment routing
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Helps replace damaged, deteriorated, or previously modified engine wiring
Vehicle Fitment
1970–1972 Chevrolet C-Series – 2WD Trucks
Potential applications include:
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1970–1972 Chevrolet C10
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1970–1972 Chevrolet C20
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1970–1972 Chevrolet C30
1970–1972 Chevrolet K-Series – 4WD Trucks
Potential applications include:
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1970–1972 Chevrolet K10
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1970–1972 Chevrolet K20
Required Vehicle Configuration
This harness is intended for trucks equipped with:
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1970–1972 Chevrolet truck electrical configuration
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V8 engine
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Automatic transmission
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HEI electronic ignition
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Compatible factory firewall wiring connections
Important: American Autowire lists part 31520H for 1970–1972 Chevrolet trucks with V8 engines and automatic transmissions. Verify your specific engine, ignition system, and electrical connections before ordering.
Designed for HEI Electronic Ignition
What Is HEI Ignition?
HEI stands for High Energy Ignition.
GM developed HEI electronic ignition as an alternative to traditional breaker-point ignition systems.
HEI distributors are a popular upgrade for classic Chevrolet V8 engines because they eliminate the periodic adjustment and replacement of conventional ignition points.
Standard 12-Volt Ignition Feed
Original points-ignition systems commonly use resistance in the ignition feed circuit to reduce current through the ignition coil.
A typical GM HEI distributor requires a suitable 12-volt ignition power supply instead.
American Autowire modifies part 31520H by replacing the original resistance wire with a standard 12-volt feed.
This modification helps accommodate the electrical requirements of a compatible HEI ignition system.
GM Large-Cap HEI Connector Included
Part 31520H includes a connector designed for a GM large-cap HEI distributor.
This makes it a suitable choice for compatible Chevrolet V8 trucks being converted from conventional points ignition to a GM-style HEI distributor.
What If I Have an Aftermarket Distributor?
Not all aftermarket electronic ignition systems use the same connectors or electrical requirements.
American Autowire notes that if you're using a distributor other than a GM large-cap HEI unit, the connector may need to be replaced.
Verify your distributor manufacturer's specifications before installation.
Designed for V8 Engines
Chevrolet V8 Application
American Autowire identifies part 31520H for 1970–1972 Chevrolet trucks equipped with V8 engines.
Engine wiring requirements can vary depending on the engine configuration and location of electrical components.
Selecting the correct engine harness helps maintain compatibility with your truck's electrical system.
What If My Truck Has a 396 V8?
American Autowire also offers part 23230H, specifically listed for 1970–1972 Chevrolet trucks equipped with a 396 V8, automatic transmission, and HEI ignition.
If your truck has a 396 V8, verify whether part 23230H is the correct harness before ordering.
What If My Truck Has a Six-Cylinder Engine?
Part 31520H is intended for V8 applications.
Six-cylinder trucks require a harness designed for their engine configuration.
What If My Truck Has an Engine Swap?
If your truck has undergone an engine swap, verify the installed engine's wiring connections, ignition requirements, and compatibility with the factory firewall connection.
Designed for Automatic Transmission Applications
American Autowire specifically lists part 31520H for trucks equipped with automatic transmissions.
Why Does Transmission Type Matter?
Engine wiring harnesses can differ between manual and automatic transmission configurations.
Depending on the vehicle, the wiring arrangement and electrical connections may vary.
Selecting the correct harness helps maintain compatibility with the truck's electrical system.
What If My Truck Has a Manual Transmission?
Part 31520H is listed for automatic transmission applications.
If your truck has a manual transmission, select the appropriate harness for that configuration.
Factory Fit Replacement Wiring
Manufactured to Original GM Specifications
American Autowire manufactures its Factory Fit engine harnesses according to original General Motors specifications.
This helps maintain the original-style electrical layout of your classic Chevrolet truck while accommodating the HEI ignition modification.
Fully Assembled and Taped
Each harness arrives fully assembled and taped, eliminating the need to construct an engine wiring harness from individual wires and terminals.
Original Firewall Connection
The harness is designed to connect at the original firewall location.
Factory-Style Engine Compartment Routing
The harness follows original-style routing through the engine compartment, helping maintain a factory-style appearance.
What Does an Engine Wiring Harness Connect?
Engine harness circuits vary depending on the vehicle's model year and equipment.
Depending on the application, an engine harness may contain wiring associated with:
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Ignition system
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Starter
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Heater blower
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Engine temperature sending unit
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Oil pressure sending unit
Important: Not every circuit is included in every harness. Consult your factory service manual or American Autowire to confirm the exact connections included with part 31520H.
Why Replace Your 1970–1972 Chevy Truck's Engine Wiring Harness?
Replace Deteriorated Original Wiring
Engine compartment wiring is exposed to heat, vibration, moisture, and contaminants.
Over time, insulation can crack, terminals can corrode, and electrical connections can deteriorate.
Replacing an aging harness provides an alternative to repairing multiple damaged wires individually.
Accommodate an HEI Ignition Conversion
If you're converting your Chevrolet V8 from points ignition to HEI, this modified harness provides a standard 12-volt ignition feed and GM large-cap distributor connector.
Maintain Transmission Compatibility
Part 31520H is designed for automatic transmission applications.
Maintain an Original-Style Appearance
American Autowire's Factory Fit harnesses are designed for restorations where original-style wiring connections and routing are important.
Important Fitment & Installation Information
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Designed for 1970–1972 Chevrolet truck applications.
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Intended for V8 engines.
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Requires an automatic transmission configuration.
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Modified for HEI electronic ignition.
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Includes a standard 12-volt ignition feed instead of the original resistance wire.
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Includes a connector for a GM large-cap HEI distributor.
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Other distributor styles may require connector modifications.
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Trucks retaining original points ignition should use the appropriate non-HEI harness.
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Manual transmission applications require verification of the correct harness.
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Six-cylinder applications require a different harness.
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The 396 V8 automatic HEI configuration has a separately listed harness, part 23230H.
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Verify compatibility if your truck has undergone an engine or transmission swap.
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Confirm original firewall connections before ordering.
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This is an engine wiring harness, not a complete vehicle wiring kit.
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Front lighting, dash, and rear lighting harnesses are separate components.
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Consult your factory service manual and distributor manufacturer's installation instructions.
Frequently Asked Questions
Will this engine wiring harness fit my 1970 Chevy C10?
It may fit if your 1970 Chevrolet C10 has a compatible V8 engine, automatic transmission, HEI ignition, and the correct factory electrical connections.
Does this harness fit a 1972 Chevy C10?
American Autowire lists part 31520H for 1970–1972 Chevrolet trucks. Verify your truck's engine, transmission, and ignition configuration before ordering.
What engine is this harness designed for?
American Autowire identifies part 31520H for Chevrolet V8 applications.
For a 396 V8, verify the separately listed part 23230H.
Will this harness fit a six-cylinder engine?
No. Part 31520H is intended for V8 applications.
Does this harness work with a manual transmission?
Part 31520H is listed for automatic transmission applications.
If your truck has a manual transmission, select the appropriate harness for that configuration.
Does this harness provide a 12-volt ignition feed?
Yes. American Autowire replaces the original ignition resistance wire with a standard 12-volt feed.
Does this harness include an HEI distributor connector?
Yes. It includes a connector for a GM large-cap HEI distributor.
Will this harness work with my original points distributor?
This harness is modified for HEI ignition.
For an original points distributor, use the appropriate non-HEI engine wiring harness.
Can I use this harness with an aftermarket HEI distributor?
Possibly. Distributors other than GM large-cap HEI units may require connector modifications.
Verify compatibility with your distributor manufacturer before ordering.
Does this harness include an HEI distributor?
No. This product is an engine wiring harness. The distributor is sold separately.
Will this fit a GMC pickup?
American Autowire lists part 31520H for Chevrolet trucks. GMC compatibility has not been confirmed.
Does this replace the entire truck wiring system?
No. This product replaces the engine wiring harness. Other vehicle wiring harnesses are separate components.
Restore Your Chevy Truck's Engine Wiring
Whether you're restoring a classic C10, replacing deteriorated engine wiring, or converting your V8-powered Chevrolet pickup to HEI electronic ignition, the American Autowire 31520H Engine Wiring Harness provides an original-style replacement designed for your truck's specified engine and transmission configuration.
Find the wiring harnesses, electrical components, and restoration parts you need at Tuckers Classic Auto Parts.
Helping Keep Classic Trucks on the Road Since 1993.