🏷️ Basic Information

Make:

Chevrolet

Model:

Corvette

Model Year:

1981

Chassis Code:

C3 (Third Generation)

Platform:

GM Y-body

Body Style:

2-door Coupe (with T-tops)

Engine Codes Covered:

LG4 (305 ci), L81 (350 ci), L82 (350 ci - optional), L31 (454 ci - C.P.O. Only)

Transmission Codes Covered:

THM-700R4 (4-speed Automatic), M20 (4-speed Manual - limited availability)

👋 Introduction

Market Position:

The 1981 Corvette represented Chevrolet's continued evolution of its iconic sports car, aiming to balance performance with increasing emissions and fuel economy regulations. It was a premium offering in the American sports car market.

Competitive Analysis:

Competed against other American performance cars and emerging European sports cars. Its C3 platform, while mature, offered a distinct American V8 performance characteristic. This manual is essential for maintaining its unique characteristics.

Key Features:

Iconic C3 styling, available powerful V8 engines, removable T-top roof panels, rear-wheel drive. The 1981 model year saw significant updates to emissions control systems and the introduction of the 700R4 automatic transmission.

📋 Manual Details

Coverage Areas:

Comprehensive coverage for all mechanical, electrical, and body systems of the 1981 Chevrolet Corvette with 305, 327 (though primarily 350ci in '81), 350, 396 (rare in '81, usually 350), 427 (not standard in '81, usually 350), 454 (CPO only) engines and applicable transmissions.

Estimated Page Count:

Hundreds of pages (specific count not provided, typical factory manuals for this era are 700-1200 pages)

Manual Type:

Factory Service Manual (FSM) / Repair Manual

Language:

English

Format:

Digital Download (PDF)

📖 Manual Coverage

Systems Covered:

Engine (all variants), Fuel System, Ignition System, Cooling System, Exhaust System, Clutch, Transmission (Manual & Automatic), Driveline, Suspension (Front & Rear), Steering, Brakes (Front Disc, Rear Disc), Electrical System (including Wiring Diagrams), Lighting, HVAC (Heating, Ventilation, Air Conditioning), Body & Frame, Interior Trim, Emissions Control Systems.

Procedures Included:

Scheduled Maintenance, Troubleshooting Diagnostics, Component Removal & Installation, Major Overhaul Procedures, Electrical System Diagnosis & Repair, Emission System Adjustment & Repair, Body Panel Alignment & Repair, Interior Component Repair, Torque Specifications, Special Tool Requirements.

Technical Depth:

In-depth, factory-level detail suitable for professional mechanics and advanced DIY enthusiasts. Covers everything from basic fluid changes to complete engine rebuilds and complex electrical system troubleshooting.

Wiring Diagrams Coverage:

Comprehensive, detailed color-coded wiring diagrams for all vehicle systems, crucial for electrical troubleshooting.

Troubleshooting Charts Availability:

Includes detailed diagnostic flowcharts and troubleshooting guides for common problems.

📊 Manual Specifications

File Format:

Portable Document Format (PDF)

Print Quality:

Designed for clear printing, allowing users to create a physical copy of the manual. Text is likely searchable and images are clear.

Binding Type:

Not applicable for PDF download, but implies a format suitable for binding if printed (e.g., tabbed sections, page numbering).

Paper Type:

Not applicable for PDF download, but factory manuals typically use durable paper to withstand shop use.

Searchable Text:

Likely includes searchable text, allowing for quick finding of specific repair procedures or specifications.

⚙️ Engine Specifications

Primary Engine Offering:

350 cubic inch (5.7L) V8

Base 350Ci Horsepower:

190 hp @ 4000 rpm (L81)

Optional 350Ci Horsepower:

200 hp @ 4000 rpm (L82 - if equipped)

Base 350Ci Torque:

280 lb-ft @ 2000 rpm (L81)

Optional 350Ci Torque:

285 lb-ft @ 3200 rpm (L82 - if equipped)

305Ci Horsepower:

155 hp @ 4000 rpm (LG4 - California/High Altitude only)

305Ci Torque:

240 lb-ft @ 2400 rpm (LG4 - California/High Altitude only)

Fuel System Type:

Rochester Quadrajet 4-barrel Carburetor (for 350ci), Rochester Dual Jet 2-barrel Carburetor (for 305ci)

Fuel Type Recommendation:

Unleaded gasoline, 87 octane (minimum) for L81, 91 octane (recommended) for L82.

Engine Block Material:

Cast Iron

Engine Design:

Overhead Valve (OHV), V8 Configuration

Ignition System:

Electronic Spark Control (ESC) with knock sensor and HEI distributor.

Emission Control Systems:

Catalytic converter, Exhaust Gas Recirculation (EGR), Electronic Spark Control (ESC), Air Injection Reaction (AIR) system. Manual provides specific diagnostic and adjustment procedures.

🔧 Transmission

Standard Transmission:

Turbo-Hydramatic THM-700R4 4-speed automatic

Optional Transmission:

Muncie M20 4-speed manual (very limited production for 1981)

Thm-700R4 Features:

Overdrive gear for improved fuel economy, lock-up torque converter.

Automatic Transmission Fluid Type:

Dexron II

M20 Gear Ratios:

Manual provides specific ratios for M20 transmission if equipped. Typical for the era: 2.85:1 (1st), 1.71:1 (2nd), 1.00:1 (3rd), 0.80:1 (4th - overdrive).

📐 Dimensions

Overall Length:

179.8 inches (4567 mm)

Overall Width:

70.6 inches (1793 mm)

Overall Height:

47.8 inches (1214 mm)

Wheelbase:

98.0 inches (2489 mm)

Curb Weight Approx:

3464 lbs (1571 kg)

Cargo Volume:

10.5 cubic feet (rear compartment)

Standard Tire Sizes:

P255/60R15 (Front and Rear). Manual will confirm specific fitments and pressures.

Wheel Bolt Pattern:

5 x 4.75 inch (5 x 120.65 mm)

🛡️ Safety Features

Safety Ratings:

NHTSA ratings for this era are not directly comparable to modern standards. Primarily focused on occupant restraint and basic crashworthiness.

Active Safety Features:

Power-assisted front disc and rear disc brakes, variable ratio power steering.

Passive Safety Features:

Seat belts (lap and shoulder), padded interior surfaces, energy-absorbing steering column.

💡 Technology Features

Infotainment System:

AM/FM radio (optional cassette player), analog gauges.

Driver Assistance Features:

Power steering, power brakes, optional cruise control.

Connectivity Features:

Not applicable in the modern sense. Primarily focused on vehicle operation.

🔧 Maintenance

Oil Change Interval:

Every 3,000 miles or 3 months (typical for the era, manual will specify exact interval)

Tune Up Interval:

Every 12,000-15,000 miles (typical for the era, manual will specify)

Transmission Fluid Change:

Every 24,000-36,000 miles or 24 months (typical for the era, manual will specify)

Engine Oil Type Capacity:

API SF, SAE 10W-30 or 10W-40 (depending on climate); 5 quarts with filter. (Manual to confirm exact capacity and viscosity recommendations).

Coolant Type:

50/50 mixture of ethylene glycol antifreeze and distilled water.

Brake Fluid Type:

DOT 3 hydraulic brake fluid.

Power Steering Fluid Type:

GM Type A Suffix A or Dexron II

Rear Axle Fluid Type:

GM Limited Slip Differential Additive and SAE 80W-90 gear oil (if equipped with Posi-traction).

Common Issues C3 1981:

Carburetor adjustment issues due to emissions controls, electrical gremlins (especially grounding), vacuum hose leaks, aging rubber components (bushings, hoses), potential carburetor flooding. The manual is critical for diagnosing and addressing these specific issues.

Base Ignition Timing:

Typically 4-6 degrees Before Top Dead Center (BTDC) for L81/L82. (Manual to confirm exact specification and procedure for adjustment with ESC system).

📚 Vehicle History

Brand Heritage:

Chevrolet has a long history of producing performance vehicles, with the Corvette being its flagship sports car since 1953. The brand is synonymous with American muscle and accessible performance.

Model Evolution C3:

The C3 generation (1968-1982) saw significant design and engineering changes throughout its run. The 1981 model year marked the final year for the iconic long-hood, short-deck design and saw advancements in emissions controls and powertrain efficiency.

Production Year:

1981

Production Location:

Bowling Green, Kentucky, USA

Units Produced 1981:

Approximately 40,606

🏆 Awards & Recognition

Historical Recognition:

The Corvette has consistently been recognized as a symbol of American automotive achievement and performance. While specific awards for the 1981 model year might be less publicized, it continued the legacy of the Corvette as a desirable sports car.