🏷️ Basic Information

Make:

Chevrolet

Model:

Corvette

Year:

1981

Engine Code:

LG4 / L81 (350ci) or ZLQ (350ci with L82 option)

Production Code:

C3 Generation (Third Generation)

👋 Introduction

Positioning:

The 1981 Corvette represented a refinement of the iconic C3 generation, focusing on improved efficiency and drivability while retaining its performance image. It was a cornerstone of American sports car culture.

Competitors:

Primarily competed with other American performance cars and imported sports cars such as the Porsche 924/944, BMW 3 Series (E21/E30), and Datsun 280ZX/300ZX.

Design Highlights:

Aggressive styling, removable T-tops, long hood, independent rear suspension, fiberglass body construction.

Powertrain Options:

Introduction of the Cross-Fire Injection system for improved fuel economy and emissions, along with the traditional carbureted V8 options.

Value Proposition:

This factory service manual is an indispensable tool for any owner or mechanic working on a 1981 Corvette, providing the authoritative information needed for accurate diagnosis, maintenance, and repair.

📋 Manual Details

General Coverage:

Complete factory service and repair for 1981 Chevrolet Corvette

Specific Systems:

Engine, Transmission, Drivetrain, Suspension, Steering, Brakes, Electrical System, Fuel System, Cooling System, Exhaust System, Climate Control, Body & Frame, Interior Components, Diagnostic Procedures, Troubleshooting Guides

Estimated Pages:

Approximately 900-1000+

Type:

Factory Service Manual / Repair Manual

Language:

English

Format:

Digital Download PDF

📖 Manual Coverage

Engine Mechanical:

Detailed disassembly, inspection, and reassembly of all engine components including block, crankshaft, pistons, connecting rods, cylinder heads, camshaft, valves, and timing set. Torque specifications and clearances provided.

Engine Performance:

Fuel injection system (Cross-Fire Injection), ignition system, emission control systems (EGR, catalytic converter operation), carburetor adjustments (if applicable to specific engine variant), engine diagnostics.

Transmission Drivetrain:

Manual and automatic transmission (THM350, THM400) overhaul, clutch service, driveshaft, universal joints, rear axle assembly, differential service, wheel bearing replacement.

Suspension Steering:

Front and rear suspension component replacement (control arms, ball joints, bushings, springs, shock absorbers), alignment specifications, steering gearbox overhaul, power steering system service.

Brakes:

Front and rear disc brake service, caliper overhaul, rotor replacement, brake booster, master cylinder, brake lines, parking brake system.

Electrical System:

Complete wiring diagrams for all circuits, battery, charging system (alternator), starting system, lighting, gauges, instrument cluster, power windows, power locks, radio, horn, windshield wipers, and diagnostic procedures for electrical faults.

Body Frame:

Frame inspection and repair, body panel removal and installation, door hinge adjustment, hood and deck lid alignment, T-top seal replacement, glass installation, interior trim panel removal and installation, bumper repair.

Maintenance:

Oil and filter changes, spark plug replacement, coolant flushes, brake fluid replacement, differential fluid change, lubrication points, tire rotation.

Troubleshooting:

Diagnostic charts and flowcharts for common drivability issues, electrical problems, and mechanical failures. Symptom-based troubleshooting guides.

Repair Rebuild:

Step-by-step instructions for major component overhauls, component replacements, and system repairs. Includes detailed diagrams and illustrations.

Depth:

Comprehensive. Covers everything from basic maintenance and tune-ups to complete engine, transmission, and chassis overhauls. Includes detailed diagnostic procedures and specifications for professional technicians.

📊 Manual Specifications

File Type:

PDF

Searchability:

Fully searchable text content for quick information retrieval.

Image Resolution:

High resolution, suitable for printing all pages or specific sections.

Binding:

Digital (printable)

Paper Quality:

N/A (Digital PDF)

⚙️ Engine Specifications

Engine Type:

Naturally Aspirated V8

Displacement:

350 cubic inches (5.7 Liters)

Bore X Stroke:

4.00 in x 3.48 in (101.6 mm x 88.4 mm)

Compression Ratio:

8.2:1 (typical for L81)

Horsepower L81:

190 hp @ 4000 rpm

Torque L81:

285 lb-ft @ 2400 rpm

Horsepower Crossfire Injection:

190 hp @ 4000 rpm

Torque Crossfire Injection:

285 lb-ft @ 2400 rpm

Fuel Induction Standard:

Cross-Fire Fuel Injection (Throttle Body Injection)

Fuel Type:

Unleaded Gasoline (87 Octane Minimum)

Cylinder Head Material:

Cast Iron

Block Material:

Cast Iron

Timing Drive:

Chain and Gear

Emission Systems:

Exhaust Gas Recirculation (EGR), Catalytic Converter, Air Injection Reactor (AIR)

🔧 Transmission

Transmission Type:

Automatic

Automatic Transmission Model:

Turbo-Hydramatic 350 (THM350) or Turbo-Hydramatic 400 (THM400)

Manual Transmission:

4-speed Manual (Muncie M20/M21 based, less common in 1981)

Automatic Gear Ratios:

Refer to manual for specific THM350/THM400 ratios (e.g., THM350: 2.52:1, 1.52:1, 1.00:1)

Automatic Transmission Fluid:

Dexron III (or equivalent)

Manual Transmission Fluid:

GL-4 Gear Oil (e.g., SAE 80W-90)

📐 Dimensions

Length:

185.1 inches (4701 mm)

Width:

70.8 inches (1798 mm)

Height:

48.5 inches (1232 mm)

Wheelbase:

98.0 inches (2489 mm)

Curb Weight:

Approximately 3400-3500 lbs (1542-1588 kg)

Gross Vehicle Weight Rating:

Approximately 4100 lbs (1860 kg)

Wheel Bolt Pattern:

5 x 4.75 inches (5 x 120.65 mm)

Standard Tire Size:

P225/70R15

🛡️ Safety Features

Crash Test Information:

As per 1981 NHTSA standards; detailed specific ratings are less commonly available in modern formats for this era. Manual covers structural integrity and component safety related to repair.

Active Safety:

Four-wheel power disc brakes, power steering.

Passive Safety:

Collapsible steering column, seat belts (lap and shoulder), shatter-resistant windshield.

💡 Technology Features

Audio System:

Factory AM/FM stereo radio, often with cassette player. Manual provides details on radio removal, installation, and wiring.

Assistance Features:

No modern electronic driver-assistance systems. Focus is on mechanical systems and driver control.

Connectivity Features:

N/A (No factory connectivity options)

Climate Control System:

Air conditioning (optional), heater, and ventilation. Manual covers component diagnosis and service for the HVAC system.

🔧 Maintenance

Oil Change Interval:

Every 3,000 miles or 3 months (whichever comes first) using high-quality oil.

Tune Up Interval:

Spark plugs, points (if applicable), and ignition timing checks typically every 10,000-15,000 miles.

Coolant Flush Interval:

Every 2 years or 30,000 miles.

Engine Oil Specification:

API SF, SAE 10W-30 or 10W-40 (check owner's manual for ambient temperature recommendations)

Engine Oil Capacity:

5 Quarts (4.7 Liters) with filter

Coolant Type:

Ethylene Glycol based antifreeze, meeting GM specification (typically a 50/50 mix with distilled water)

Brake Fluid Type:

DOT 3

Common Corrosion Areas:

Frame rails, especially around suspension mounting points and rear differential. Fiberglass body can be susceptible to cracking from impact or stress.

Electrical Gremlins:

Age-related electrical issues are common, including faulty grounds, deteriorating wire insulation, and malfunctioning dashboard components. The manual's wiring diagrams are crucial for diagnosis.

Fuel System Challenges:

Cross-Fire Injection system can be sensitive to fuel pressure issues, clogged injectors, and sensor failures. Carbureted versions may require periodic adjustments.

Vacuum Leaks:

Age of vacuum hoses can lead to leaks, affecting engine performance and emissions. The manual details the location and routing of all vacuum lines.

📚 Vehicle History

Chevrolet Legacy:

Chevrolet has a long history of performance vehicles, with the Corvette being its flagship sports car since its inception in 1953, consistently pushing boundaries in design and engineering.

C3 Generation Context:

The 1981 model year was toward the end of the third generation (C3), which ran from 1968 to 1982. This era saw significant evolution in powertrain technology, emissions control, and refinement, including the introduction of electronic fuel injection.

Production Years:

1968-1982 (C3 Generation)

1981 Production Volume:

Approximately 40,606 units

Assembly Location:

Bowling Green, Kentucky, USA

🏆 Awards & Recognition

Classic Car Status:

The 1981 Corvette is recognized as a significant classic American sports car, valued for its styling and performance heritage. It's a popular entry into vintage racing and car shows.

Owner Satisfaction Legacy:

While specific ratings from 1981 are scarce, the C3 generation is generally appreciated for its iconic styling and V8 performance, though often noted for its less refined handling compared to later generations or European counterparts.