🏷️ Basic Information

Make:

Chevrolet

Model:

Corvette

Model Variant:

Sting Ray (C3)

Year:

1968

Engine Code Represented:

L36 (427), L68 (427), L71 (427), L88 (427)

Production Code Represented:

427, 454 (common colloquialism for 427 cubic inch engines)

👋 Introduction

Vehicle Segment:

American Sports Car, High-Performance GT

Target Audience:

Enthusiasts, collectors, restorers, owners seeking to maintain or repair their 1968 Corvette.

Key Competitors Era:

Ford Mustang, Shelby Mustang, Mercury Cougar, Pontiac Firebird, Dodge Charger, Plymouth Barracuda.

Iconic Status:

The 1968 Corvette represents the debut of the C3 generation, a significant design shift, and is highly sought after by collectors.

Performance Focus:

Emphasis on powerful V8 engines, particularly the potent 427 cubic inch variants, cementing its reputation as a true muscle car.

Design Evolution:

Introduction of the C3's flowing body lines, hidden headlights, and removable T-top roof panels.

📋 Manual Details

Manual Type:

Workshop Repair Service Manual

Language:

English

Format:

PDF Download

Comprehensive Coverage:

All Models, Engines, Trim, Transmissions

📖 Manual Coverage

Engine Mechanical:

Engine overhaul, disassembly, assembly, lubrication systems, cooling systems, fuel systems (carburetor and ignition timing for 427 V8s), emission control systems (where applicable).

Engine Performance:

Tuning procedures, diagnostic charts for performance issues, carburetor adjustment and rebuilding, ignition system troubleshooting.

Transmission Manual:

Service and overhaul of Muncie 4-speed and 3-speed manual transmissions, clutch system service.

Transmission Automatic:

Service and overhaul of Turbo-Hydra-Matic 3-speed automatic transmission (e.g., TH400), including adjustments and troubleshooting.

Drivetrain:

Rear axle service (e.g., positraction differential), driveshaft, universal joints, half-shafts.

Suspension:

Front and rear suspension systems, ball joints, control arms, bushings, shock absorbers, springs, steering linkage.

Steering:

Steering gearbox service (e.g., Saginaw), power steering system, steering wheel, column.

Brakes:

Front and rear brake systems (disc and drum), brake fluid specifications, bleeding procedures, caliper and wheel cylinder service, parking brake.

Electrical:

Wiring diagrams, starter, alternator, battery service, lighting systems, horn, windshield wipers, gauges, radio service, troubleshooting of electrical faults.

Fuel System:

Fuel tank, fuel lines, fuel pump, carburetor systems (e.g., Holley, Rochester Quadrajet), fuel filter replacement.

Body Exterior:

Body panel removal and installation, doors, hood, T-tops (if applicable), bumpers, glass replacement, weather stripping, convertible top mechanism.

Body Interior:

Dashboard, seats, trim panels, carpet, door panels, console removal and installation.

Heating Ventilation Air Conditioning:

HVAC system diagnosis and repair, heater core, blower motor, ducting, air conditioning system service (if factory equipped).

Exhaust:

Exhaust system components, mufflers, pipes, catalytic converters (where applicable for the era), exhaust manifold repair.

Routine Maintenance:

Oil changes, filter replacements, fluid level checks and top-offs, lubrication points, tune-ups.

Component Overhaul:

Complete engine rebuilding procedures, transmission disassembly and reassembly, brake caliper and master cylinder overhauls.

Troubleshooting Diagnostics:

Systematic diagnostic flowcharts for common and complex issues, identification of causes for poor performance, noise diagnosis.

Adjustment Settings:

Carburetor idle speed and mixture adjustments, ignition timing adjustments, valve lash adjustments, clutch pedal adjustment.

Replacement Installation:

Component replacement procedures for virtually all major systems, including engine mounts, radiator, water pump, starter, alternator, fuel pump, brake pads, suspension arms.

Wiring Diagram Interpretation:

Detailed explanation and application of electrical schematics for troubleshooting and repair.

Torquewrench Specifications:

Crucial torque specifications for engine components, chassis fasteners, suspension and brake assemblies.

Depth Level:

Comprehensive, from basic maintenance to complete engine and transmission rebuilds, including detailed diagnostic procedures and factory specifications.

Diagnostic Tools Required:

Specifies tools and equipment needed for various repairs and diagnostics, often including specialized tools.

📊 Manual Specifications

File Type:

PDF

Searchable Text:

Likely to contain searchable text for efficient information retrieval.

Printability:

Designed to be printable for workshop use.

Resolution Quality:

Professional quality scans or digital reproductions, ensuring clarity of diagrams and text.

Binding Type:

N/A (Digital Download)

Paper Type:

N/A (Digital Download)

⚙️ Engine Specifications

Engine Displacement Options:

427 cubic inches (7.0 Liters)

Engine Type:

Naturally Aspirated Overhead Valve (OHV) V8

L36 (427):

390 hp @ 4800 rpm, 470 lb-ft @ 3200 rpm (1x4 barrel Rochester carburetor)

L68 (427):

400 hp @ 5000 rpm, 460 lb-ft @ 3600 rpm (3x2 barrel Rochester carburetors - Tri-Power)

L71 (427):

435 hp @ 5400 rpm, 460 lb-ft @ 4200 rpm (3x2 barrel Holley carburetors - Tri-Power)

L88 (427):

430 hp @ 5400 rpm, 470 lb-ft @ 3600 rpm (1x4 barrel Holley carburetor, high-compression, L71 block with forged crank, rods, pistons, high-lift cam). Note: Advertised hp for L88 was often conservative.

Carburetor Options:

Rochester Quadrajet (1x4bbl), Rochester Tri-Power (3x2bbl), Holley (1x4bbl, 3x2bbl)

Fuel Requirement:

Premium Unleaded Gasoline (historically, leaded premium was required for higher compression engines like L71/L88)

🔧 Transmission

Transmission Type Standard:

Muncie SM465 4-speed manual (often) or BorgWarner T-10 4-speed manual (optional/earlier), Turbo-Hydra-Matic 350/400 3-speed automatic (optional)

Transmission Type Optional:

Turbo-Hydra-Matic 350 (TH350) or Turbo-Hydra-Matic 400 (TH400) 3-speed automatic, Muncie 3-speed manual (less common for 427 models)

Clutch Type:

Single dry plate diaphragm clutch (manual transmission)

Gear Ratios:

Vary by transmission and rear axle ratio; Muncie 4-speeds typically had close-ratio options (e.g., 2.20:1 low gear).

📐 Dimensions

Length:

175.9 inches (4468 mm)

Width:

69.1 inches (1755 mm)

Height:

47.9 inches (1217 mm)

Wheelbase:

98.0 inches (2489 mm)

Curb Weight:

Approximately 3,000-3,400 lbs (1361-1542 kg), depending on engine and options.

🛡️ Safety Features

Crash Testing Era:

Modern crash safety standards were not as rigorously enforced or standardized in 1968. Data is limited and not comparable to today's ratings.

Brakes:

Four-wheel disc brakes standard (e.g., Delco-Moraine), power assist optional.

Steering System:

Recirculating ball steering, optional power steering for reduced effort.

Seat Belts:

Standard seat belts (lap belts).

Safety Glass:

Laminated safety glass for windshield.

Collapsible Steering Column:

Introduced for improved crashworthiness.

💡 Technology Features

Radio:

AM/FM mono radio, optional AM/FM pushbutton radio, optional 8-track tape player. Units often replaced with modern aftermarket units.

Gauges:

Full complement of analog gauges including speedometer, tachometer, oil pressure, water temperature, ammeter, and fuel gauge.

Cruise Control:

Optional cruise control system available.

Connectivity Features:

None in the modern sense. Primarily focused on mechanical and electrical systems.

🔧 Maintenance

Oil Change Interval:

Recommended every 3,000 miles or 6 months, whichever comes first. High-performance engines may benefit from more frequent changes.

Tune Up Interval:

Typically every 12,000-24,000 miles, involving spark plugs, points, condenser, timing adjustment, and carburetor adjustment.

Transmission Fluid Change:

Manual: Check level regularly, change if contaminated. Automatic: Change fluid and filter every 24,000-36,000 miles.

Engine Oil:

API SG or higher, SAE 10W-30 or 10W-40 for most conditions. For L88/high-performance, a high-zinc, high-detergent oil (like racing oil) is recommended. Capacity: approx. 5 quarts with filter.

Coolant:

Ethylene glycol based antifreeze, mixed 50/50 with distilled water. Capacity: approx. 20-22 quarts.

Brake Fluid:

DOT 3 or DOT 4 hydraulic brake fluid.

Transmission Fluid Manual:

GL-4 or GL-5 gear oil (e.g., SAE 80W-90).

Transmission Fluid Automatic:

Dexron-III (or equivalent) automatic transmission fluid. Capacity: approx. 4-5 quarts without torque converter drain.

Rear Axle Fluid:

GL-5 gear oil (SAE 90 or 80W-90). If Positraction, use appropriate limited-slip additive. Capacity: approx. 3 pints.

Carburetor Issues:

Vapor lock, fuel delivery issues, tuning difficulties with multiple carburetors, vacuum leaks.

Electrical Gremlins:

Failing wiring insulation, corroded connections, switch failures are common in older vehicles.

Suspension Wear:

Worn ball joints, control arm bushings, and tie rod ends can lead to alignment issues and poor handling.

Brake System:

Corroded brake lines, sticking calipers, and worn rotors/pads are prevalent due to age and environmental factors.

Fiberglass Body Cracks:

Stress cracks, particularly around wheel wells and body seams, can occur over time.

📚 Vehicle History

Chevrolet Legacy:

Chevrolet, a division of General Motors, has a long history of producing performance vehicles and American icons, with the Corvette being its flagship sports car since 1953.

C3 Introduction:

The 1968 model year marked the introduction of the third-generation Corvette (C3), codenamed 'Mako Shark II' after the concept car. It featured a completely new body style.

Engine Development:

The 427 cubic inch engine was a potent offering, building on Chevrolet's big-block V8 lineage, with the L88 being a rare, racing-oriented variant.

Production Period:

1968-1982 (C3 Generation)

Manufacturing Location:

St. Louis, Missouri, USA

1968 Production Volume:

Approximately 28,566 Corvettes produced for 1968.

🏆 Awards & Recognition

Classic Car Status:

Highly regarded as a collector's item and a significant piece of automotive history, frequently featured in classic car publications and awards.

Performance Reputation:

Celebrated for its powerful engine options and sporty handling, earning its place as an American icon.