A significant milestone coinciding with the arrival of the 1977 Corvette happened in a year that was full of impressive milestones. On May 25, 1977, the film world would be changed forever as audiences were transported to a “galaxy far, far away” in George Lucas’s outer space epic, “Star Wars.”
Just four days later, race car driver A.J. Foyt would become the first driver to win the Indianapolis 500 four times. The Apple Computer would officially begin its rise to global fortune and fame while the Commodore company introduced the world to its first personal, all-in-one computer, the “Commodore PET”. Even rival automotive manufacturer Porsche was reaching new milestones with the introduction of their first front-engine, V8 powered car, the 928 at the Geneva Motor Show on September 28th.
For Chevrolet, however, the 1977 model year marked a significant manufacturing milestone – the production of their 500,000th Corvette. It had taken Chevrolet 15 years to build the first 250,000 Corvettes, but only an additional eight years to build 250,000 more. While the 250,000th Corvette had been a Riverside Gold convertible that had been built on November 7, 1969, the 500,000th Corvette was a white coupe, which was driven off the production line by (then) Chevrolet General Manager, Robert Lund on March 15, 1977.
Ironically, the Corvette had nearly been pulled from Chevrolet’s lineup in those early years of its production, despite the prosperous post-war economy of America in the mid-1950’s. Adding to the irony was the fact that the Corvette had actually flourished throughout difficult economic times, even in periods when rival automotive manufacturers were pulling the performance-car models from their ranks.
While it was true that the Corvette’s performance had certainly dwindled – especially over the past couple of years, to a modest shadow of its big-block older brothers from the 1960’s, there was no question that the car’s appeal had only grown with each passing year.
The 1977 C3 Corvette arrived with only a few, modest modifications from its previous year. Outwardly, the car was virtually identical to the 1976 model, save for the introduction of a reworked luggage and roof panel rack (RPO V54) that could be used to transport the car’s T-tops (instead of placing them in the Corvette’s lidless trunk.)
DID YOU KNOW: The 500,000th Corvette, a white 1977 coupe, rolled off the St. Louis assembly line at 2:01 P.M. on March 15th, 1977.
With regard to the T-tops, glass roof panels were introduced as a new option at the start of the model year, though General Motors later canceled the option because of a reputed dispute with the supplier over sales rights. The most notable change from 1976 to 1977, however, was the removal of the Stingray nameplate from the Corvette’s front fenders. It was replaced by Corvette’s traditional crossed-flags insignia.
The changes to the interior were equally subtle, though there were a few more modifications worth noting. First, the interior center radio console was redesigned to accept a broader array of Delco audio decks (including an AM/FM/cassette stereo as a first-time option).
The instruments on the dashboard were restyled to provide drivers greater visibility. The climate controls were simplified.
Moving down the center column, the manual transmission lever was lengthened, placing the shifter ball higher up in relation to the disengaged handbrake. Previously, the shorter shifter shaft had caused interference when drivers attempted to actuate the parking brake lever. By lengthening the shifter lever, the parking brake accessibility was improved, making it easier to engage and disengage.
Elsewhere, the steering column itself was shortened by two inches to allow for more of an “arms out” driving posture, (which helps drivers reduce the risk driver injury during a potentially dangerous situation.)
Additionally, the shorter steering column improved driver accessibility in-to, and out-of, the new Corvette. Mated to the steering column was a new leather rimmed steering wheel. For those consumers that ordered the optional tilt-telescopic steering column (RPO N37), the 1976 style steering wheel remained the only choice. While tilt and telescopic adjustments remained optional, Chevrolet did introduce a new feature to the 1977 Corvette – namely the new “Smart Switch” – a steering column stalk that combined the headlight dimmer and wiper/washer functions with the turn signals.
The alarm switch was moved again and was incorporated into the left door-lock button assembly. Additionally, the sun visors were revamped to allow them to swing from the windshield to the side windows. Even the mounting location of the rearview mirror was shifted from above the windshield to the windshield itself. Lastly, for the 1977 model year leather upholstery came standard with the Corvette while cloth seats with leather bolsters were an optional no-cost alternative.
Mechanically, the 1977 Corvette went essentially unchanged from the 1976 model year. As in 1976, the 1977 Corvette came standard with a 180 horsepower, 350 cubic-inch, small-block Chevy engine mated to a 4-speed, wide-ratio manual transmission.
Also like the 1976 model, the new Corvette could be ordered with an optional 210 horsepower engine (PRO L48), except in Canada where the base engine remained the only available option due to higher emission standards.
While the engines remained the same, there was an interesting turn of events within General Motors that occurred early in the 1977 model year’s production run. Between August 23 and September 7, 1976, Flint Engine (the plant where the small-block 350 was manufactured) began using blue paint in place of the traditional “Chevy Orange” paint that had normally been applied to Corvette engines. Thus, early 1977 model year Corvettes continued to feature the familiar orange, while later production engines were blue.
The 1977 Corvette set another new sales record at 49,213 units. The popularity of the Chevy Corvette throughout the 1970’s was proven time and again by the year over year increase in sales numbers despite the dramatic increases in cost.
In 1974, the base sticker price of the Corvette had crossed the $6,000 barrier for the first time (it was actually $6,001.50). With each year, the price increase had been notable – $6,810.10 in 1975, $7,604.85 in 1976, and $8,647.65 in 1977, due to the inclusion of so many standard comfort and convenience features. Despite this, there was no question that the popularity of the Corvette was still on the rise – which was doubly amazing (though not surprising) given that the C3 Corvette was a decade old.
Uniconstruction: fiberglass reinforced plastic (FRP or “fiberglass”) body, backboned by a steel cage outlining the passenger compartment. Principal members – underbody, front and rear end assemblies, dash panel and hinge pillars are bonded, riveted, or bolted together and to each other. Hood is plastic with bonded plastic reinforcement. Coupe: two removable roof panels and removable rear window. Frame: all welded, full length, ladder construction with 5 crossmembers. Side Rails and intermediate crossmembers box section; front crossmember box girder section. Eight body-mounting points.
Type and Description: Independent, SLA type, coil springs with center mounted shock absorbers, spherical joint steering knuckle pivots.
Front Coil Springs
Make & Type
10.27 x 3.80; 130.84 x 0.606
Front Stabilizer Bar
Hot rolled steel
Suspension – Back
Type and Description: Full Independent rear suspension with frame-anchored differential unit. Position of each wheel established by three links: tubular axle drive shafts, transverse strut rods, torque control arms. Vertical suspension loads taken by transverse leaf springs. Built-in camber adjustment at strut rod inner ends.
Rear Leaf Springs
Number of Leaves
Variable rate 9-leaf
Chrome carbon steel
Length, width, height
48.60 x 2.25 x 2.121
Caliper Disk – 4 Wheel Dual Hydraulic with Pressure Differential and Warning Light
Delco Moraine, vacuum power unit; integral
Drum diameter, front (in.):
11.75 x 1.25
Drum diameter, rear (in.):
11.75 x 1.25
Swept Drum Area Effective area:
Wheels & Tires
Wheels & Tires Specs
Short spoke spider, welded steel
15″ x 8.00
15″ x 8.00
GR70 x 15B — Blackwall Steel Belted Radial
GR70 x 15B — White Letter Steel Belted Radial
24 psi (cold), 30 psi (hot)
24 psi (cold), 30 psi (hot)
Steering Specs – Manual Steering
Integral, recirculating ball nut with hydraulic pressure provided from a vane type pump.
Wheel Diameter (in.)
14.75 x 14.25
Turns, Stop to Stop
37 ft. (outside front), 38.6 ft. (outside front)
1977 Corvette Exterior Dimensions
Exterior Dimensions (Coupe)
Interior Dimensions (Coupe)
Total Body Width:
Front Track Width:
Rear Track Width:
Min. Ground Clearance
2 – Driver & Passenger
Curb Weight (lbs)
Interior Passenger Volume (cu. ft)
Interior Trunk Volume (cu. ft)
Fuel Capacity (gallons):
4.0 (capacity of crankcase less filter – refill)
4.5 (capacity of crankcase refill with filter change)
Coolant capacity without heater (qts.)
12 Volt, 78 Plates, 3,500 Watts for Standard
12 Volt, 90 Plates, 4,000 Watts for Heavy Duty
Vehicle Assembly Location. S – St. Louis, Missouri
4XXXXX (Eighth thru Thirteenth Digits)
Plant Sequence Numbers.
The last six digits begin at 400001 and run thru 449213, accounting for 49,213 Corvette Coupes built in 1977. Each Vehicle Identification Number (VIN) is unique to an individual car.
1977 Corvette Vehicle Serial Number Plate
For all 1977 Corvettes, the location of the Vehicle Identification Number (VIN) is stamped on a plate attached to the left front body hinge pillar.
1977 Corvette Body Number & Point Plate
On the driver’s side upper left-hand door hinge pillar.
A01 – Body build date code.
A – Designates the Month (See Chart Below).
A – Aug., 1976B – Sep., 1976C – Oct., 1976D – Nov., 1976E – Dec., 1976F – Jan., 1977, G – Feb., 1977H – Mar., 1977 I – Apr., 1977 J – May, 1977 K – June, 1977 L – Jul., 1977, M – Aug., 1977
01 – Designates the Day of the Month.
19V – Interior Trim code. 19V – Black (Cloth)
10L – Exterior Color Code. 10 – Classic White
Codes were often followed by the letter L, but some trim plates had an exterior code preceded by the number 9 with no letter L following.
1977 Corvette Factory Options
Base Corvette Sport Coupe
Color Keyed Floor Mats
Rear Window Defogger
350ci, 210hp Engine
4-Speed Manual Trans, Close Ratio
Turbo Hydra-Matic Automatic Transmission
High-Altitude Emission Equipment
Tilt-Telescopic Steering Column
White Letter Steel Belted Tires, GR70x15
Heavy Duty Battery
AM-FM Radio, stereo
AM-FM Radio, stereo with 8-track tape
Luggage and Roof Panel Rack
California Emission Certification
Aluminum Wheels (4)
Base Corvette Sport Coupe (1YZ37)
The base price of the 1977 Chevrolet Corvette Coupe without any optional equipment.
A 350 cubic inch, 180 horsepower engine, 4-speed wide ratio manual transmission, leather interior trim, and T-tops were included in the base price.
Leather seats were standard for the first time in 1977, but a cloth-leather combination could be substituted at no additional cost.
The only engine-transmission combination available in California was the base 350 cubic-inch, 180 horsepower engine with the Turbo Hydra-Matic Automatic Transmission.
Power Windows (A31)
Factory installed power driver and passenger windows.
Color Keyed Floor Mats (B32)
Floor mats colored to match the vehicle’s interior trim coloring.
Rear Window Defroster (C49)
An optional rear window forced air defogger.
This option used glass heating elements instead of forced air and the naming convention changed from “defroster” to “defogger”.
Air Conditioning (C60)
Factory installed, four-season air-conditioning.
System includes evaporator, blower, condenser, receiver-dehydrator, refrigerant (freon) tank, air intake assembly and duct assembly for both systems.
Includes an integrated heater.
Sport Mirrors (D35)
Outside mirror assembly that included a mechanical linkage to control movement from inside the cockpit.
Gymkhana Suspension (FE7)
An optional, heavier-duty suspension system for higher levels of performance.
The Gymkhana rear leaf springs contained 9 leafs, though the top leaf is very small. GM identifies the rear leaf springs as an 8-leaf spring.
Included a stiffer front sway bar and stiffer springs.
There were no restrictions on ordering this option – it could be ordered with any engine/transmission combination.
Optional Rear Axle Ratios (G95)
A selection of optional rear axle ratios.
In 1977, these included: 3.08 (Code OA), 3.36 (Code OD), 3.36 (Code LR), 3.55 (Code OB), and 3.70 (Code OC)
Speed Control (K30)
An early version of (what is commonly known today as) cruise control.
The speed control option required an automatic transmission.
350ci, 210hp Engine (L82)
Optional higher-output, small block V-8 engine.
4-Speed Manual Transmission, Close Ratio (M21)
A close ratio version of the M20 Muncie 4-speed manual transmission.
The gear ratios for the RPO M21 Close Ratio 4-Speed Manual Transmission are: 1st Gear – 2.20:1, 2nd Gear – 1.64:1, 3rd Gear – 1.28:1, 4th Gear – 1.0:1 (Direct).
M21 was a no-cost option but required the optional L82 engine.
Turbo Hydra-Matic Automatic Transmission (M40)
An optional, three-speed automatic transmission.
The Turbo Hydra-Matic Automatic Transmission consisted of a 3-element hydraulic torque converter and compound planetary gear set. It was equipped with the following gear ratios: 1st Gear – 2.48:1, 2nd Gear – 1.48:1, and 3rd Gear – 1.00:1.
The M40 Turbo Hydra-Matic Automatic Transmission was a no-cost option with the base 350 cubic inch, 180 horsepower engine, but cost $146.00 with the optional L82 engine.
High Altitude Emission Equipment (NA6)
Alternate emission equipment installed for vehicles operating at high altitudes.
The high-altitude emission equipment was required for vehicle operation at +4,000 feet.
It was only available with the base 350 cubic inch, 180 horsepower engine and M40 transmission.
Tilt Telescopic Steering Column (N37)
An optional, adjustable steering column and tilt-angle adjustable steering wheel.
The Telescopic Steering Column changes the drivers distance from the steering wheel by literally telescoping the steering wheel closer to or further away from the vehicle operator.
A new steering column positioned the steering wheel two inches closer to the instrument panel to provide more of an “arms out” driving position, and easier entry and exit.
1977 models without option N37 were equipped with 1976 style steering wheels.
White Letter Steel Belted Tires, GR70x15 (QRZ)
Standard size tires with special raised white lettering.
Heavy Duty Battery (UA1)
Optional, heavier-duty battery with increased cranking amps/capability.
AM-FM Radio, Stereo (U58)
A standard/stock dealer installed Corvette radio.
The radio received broadcast in FM 2-channel stereo, FM monaural, and AM monaural.
16-transistor 9-diode circuitry.
Fixed height rear antenna.
In 1977, 1248 Corvettes were ordered without a radio.
AM-FM Radio (U69)
A standard/stock dealer installed Corvette radio.
The radio receives broadcast in FM monaural, and AM monaural.
16-transistor 9-diode circuitry.
Fixed height rear antenna.
In 1977, 1248 Corvettes were ordered without a radio.
AM-FM Radio, Stereo with 8-Track Tape (UM2)
The standard/stock radio equipped with an 8-Track Tape Player
In 1977, 1248 Corvettes were ordered without a radio.
Luggage and Roof Panel Rack (V54)
Externally mounted roof and luggage storage rack on the rear decklid of the car.
The roof rack was designed to hold the T-top panels, permitting use of the full luggage compartment when the roof panels were removed
California Emission Certification (YF5) –
Aluminum Wheels (4) (YJ8)
Included four aluminum wheels and a conventional steel spare.
The aluminum wheels were originally expected for arrival as an option on the 1973 Corvette.
The wheels were developed by Kelsey Hayes in Mexico.
The wheels can be identified on their inside surfaces as to source and build location.
Trailer Package (ZN1)
Factory installed trailer package.
The trailer package included the Gymkhana Suspension, a higher-amp alternator and a heavy-duty radiator.
The hitch was the standard, factory installed hitch available in 1977.
The hitch could support approximately 100 pounds of tongue weight.
Convenience Group (ZX2)
A group of convenience options available to consumers when purchasing a 1977 Corvette.
The ZX2 Convenience Group included the dome light delay, headlight warning buzzer, underhood light, low fuel warning light, interior courtesy lights, and the passenger side visor mirror. Early in production, the low-fuel warning light wasn’t available, so Chevrolet deleted it and reduced the cost of the option to $18.00. Quantity of low-fuel light deletes was 3,881.
A new console held heater and air conditioning controls and accepted standard Delco radios due to its increased depth.
Early 1977 option listings contained CC1 glass roof panels ($200.00) but these were never available during the 1977 model year due to a marketing exclusivity dispute between Chevrolet and the panel vendor.
Effective with 1Z37X7S427373, the alarm activator was moved from the driver-side fender to the driver-side door lock.
Between August 23 and September 7, 1976, Flint Engine changed from orange paint to blue when painting the Corvette engine blocks. As such, early 1977 Corvette engine blocks were orange while later production engines were blue.
The headlight dimmer and windshield wiper/washer controls were located on the steering column stalks.
Sunshades were redesigned to permit swinging to the side windows.
The interior rearview mirror mounting point was relocated from above the windshield to the windshield itself.
1977 Corvette Recalls
Make: CHEVROLET Model: CORVETTE Model Year: 1977 Manufacturer: CARDONE INDUSTRIES, INC. Mfr’s Report Date: MAY 07, 2003 NHTSA CAMPAIGN ID Number: 03E032000 NHTSA Action Number: N/A Component: SERVICE BRAKES, AIR:DISC:CALIPER Potential Number of Units Affected: 15899
REMANUFACTURERD REAR BRAKE CALIPERS, PART NOS. 18-7019, 18-7020, 16-7019, AND 16-7020, MANUFACTURED FROM FEBRUARY 1, 2002, TO APRIL, 25, 2003., AND FOR USE ON 1965 THRU 1982 CHEVROLET CORVETTES. THE SUBJECT BRAKE CALIPERS WERE MANUFACTURED USING IMPROPERLY MANUFACTURED PISTON SEALS. THESE SEALS ARE INTENDED TO PREVENT FLUID LEAKAGE BETWEEN THE CALIPER HOUSING AND THE PISTONS. THESE BRAKE CALIPERS ARE FOR USE ONLY ON 1965 THRU 1982 CHEVROLET CORVETTE VEHICLES. THIS RECALL DOES NOT INVOLVE GENERAL MOTORS CORPORATION OR ANY OF ITS PRODUCTS.
UNDER THESE CONDITIONS, THE VEHICLE OPERATOR MAY NOT BE ABLE TO STOP THE CAR, POSSIBLY RESULTING IN A VEHICLE CRASH.
CARDONE WILL NOTIFY ITS CUSTOMERS AND ALL UNSOLD INVENTORY WILL BE REPURCHASED AND WILL PROVIDE A FULL REFUND TO CUSTOMERS. OWNER NOTIFICATION IS EXPECTED TO BEGIN DURING MAY 2003. OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT CARDONE AT 215-912-3000.
ALSO, CUSTOMERS CAN CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION¿S AUTO SAFETY HOTLINE AT 1-888-DASH-2-DOT (1-888-327-4236).
Make: CHEVROLET Model: CORVETTE Model Year: 1977 Manufacturer: HONEYWELL INTERNATIONAL, INC. Mfr’s Report Date: OCT 19, 2007 NHTSA CAMPAIGN ID Number: 07E088000 NHTSA Action Number: N/A Component: EQUIPMENT Potential Number of Units Affected: 121680
CERTAIN HONEYWELL FRAM RACING BRAND HP4 AND HP8 OIL FILTERS THAT WERE MANUFACTURED FROM MAY 25, 2006, THROUGH SEPTEMBER 14, 2007, AND SOLD FOR USE AS REPLACEMENT EQUIPMENT FOR VEHICLES LIST ABOVE. THE AFFECTED FILTERS ARE MARKED WITH A DATE CODE A61451 THROUGH A72571 SEQUENTIALLY. THE DATE CODE AND PART NUMBER APPEAR ON THE FILTER HOUSING. FRAM RACING HP4 AND HP8 OIL FILTERS NOT BEARING A DATE CODE IN THIS RANGE ARE NOT AFFECTED BY THIS RECALL. THE GASKET OF THE OIL FILTER BECOMES MORE PLIABLE UNDER HIGH TEMPERATURES AND PRESSURES.
THIS CONDITION MAY CAUSE INADEQUATE SEALING AND LOSS OF ENGINE OIL, POSSIBLY RESULTING IN A FIRE.
HONEYWELL WILL REPLACE THE AFFECTED OIL FILTERS FREE OF CHARGE. THE RECALL BEGAN DURING NOVEMBER 2007. OWNERS CAN CONTACT FRAM CUSTOMER SERVICE TOLL-FREE AT 1-800-890-2075.
CUSTOMERS MAY CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION’S VEHICLE SAFETY HOTLINE AT 1-888-327-4236 (TTY: 1-800-424-9153); OR GO TO HTTP://WWW.SAFERCAR.GOV.
Make: CHEVROLET Model: CORVETTE Model Year: 1977 Manufacturer: GENERAL MOTORS CORP. Mfr’s Report Date: JUL 25, 1977 NHTSA CAMPAIGN ID Number: 77V115000 NHTSA Action Number: N/A Component: COMMUNICATIONS:HORN ASSEMBLY Potential Number of Units Affected: 15484
THE INVOLVED VEHICLES HAVE STEERING WHEEL CENTER HUBS WHICH FAIL TO CONFORM TO FEDERAL MOTOR VEHICLE SAFETY STANDARD NO. 107, “REFLECTING SURFACES”. THE HORN BUTTON CAP AND THE LOCK LEVER HAVE A BRUSHED CHROME FINISH. THE SURFACE REFLECTIVITY OF THIS FINISH ON SOME OF THESE HORN BUTTON CAPS AND LOCK LEVERS IS APPROXIMATELY TWICE THE MAXIMUM REFLECTIVITY ALLOWED BY THE STANDARD.
DEALER WILL REPLACE THE CAP AND LEVER WITH PARTS PAINTED TO MATCH THE INTERIOR TRIM COLOR AT NO COST TO OWNER.
VEHICLE DESCRIPTION: PASSENGER VEHICLES EQUIPPED WITH TILT TELESCOPING STEERINGASSEMBLY.SYSTEM: STEERING; STEERING WHEEL CENTER HUB.CONSEQUENCES OF DEFECT: IF THE DRIVER DOES NOT TAKE STEPS TO ALLEVIATE THE DISTRACTION OF LIGHT REFLECTING OFF THE STEERING WHEEL HUB, THIS COULD LEAD TOAN ACCIDENT.
1977 Corvette Service Bulletins
1977 Corvette Common Issues
1977 Corvette Maintenance Schedule
The time or mileage intervals indicated on this website are intended as a guide for establishing regular maintenance and lubrication periods. Sustained heavy duty or high speed driving, or driving under adverse conditions may require more frequent servicing.
Additional Maintenance and Lubrication
In addition to the items listed above, it is also recommended that the following items are inspected every 300 miles or 2 weeks, whichever comes first:
Check Tire Pressure
Check Battery Water Level
Check Oil Level In Engine
Remove air cleaner and block throttle and choke in wide open position. Hook up starter remote control cable and insert compression gauge firmly in spark plug port. Whenever the engine is cranked remotely at the starter, with a jumper cable or other means, the distributor primary lead must be disconnected from the negative post on the coil and the ignition switch must be in the “ON” position. Failure to do this will result in a damaged grounding circuit in the ignition switch.
Crank engine through at least four compression strokes to obtain highest possible reading. Check and record compression of each cylinder. If one or more cylinders reads low or uneven, inject about a tablespoon of engine oil on top of pistons in low reading cylinders (through spark plug port.) Crank engine several times and recheck compression. If compression comes up but does not necessarily reach normal, rings are worn. If compression does not improve, valves are burnt, sticking or not sealing properly. If two adjacent cylinders indicate low compression, the cause may be a head gasket leak between the cylinders. Engine coolant and/or oil in cylinders could result from this defect.
The adjustments described apply to all carburetors used, except as noted. All adjustments are made with the engine at normal operating temperature.
Idle Speed (1977-1979)
See emission label on vehicle. Set engine for adjustments. Set ignition timing. For carburetors without solenoid and with air conditioner off, turn idle speed screw to set curb idle speed to specifications. For carburetors with solenoid, energize the solenoid, disconnect the air conditioner at the compressor, turn air condition on, set A/T in drive, M/T in neutral and turn solenoid screw to adjust speed to specified RPM.
Idle Mixture (1977-1979)
Idle mixture screws have been preset at the factory and capped. Do not remove the caps during normal engine maintenance. Idle mixture should be adjusted only in the case of major carburetor overhaul, throttle body replacement or high idle CO level as determined by inspection
Idle Speed and Mixture – Holley 2300
All adjustments are same as previously described except as follows: On models equipped with idle stop solenoid, adjust idle stop solenoid screw to give 1000 rpm, then adjust idle mixture adjusting screw to specified rpm. Turn idle mixture screw in (leaner mixture) until engine speed drops 20 rpm, then turn out 1/4 turn. Disconnect lead at idle stop solenoid (throttle level will rest against regular stopscrew.) Adjust this stopscrew for idle speed of 500 rpm. Do not change setting of idle stop solenoid stopscrew or idle mixture screw.
Fast Idle (1977-1979)
Use choke valve measuring gage J-26701. Rotate degree scale of tool until zero is opposite pointer. With choke completely closed place magnet squarely on top of choke valve. Rotate bubble until it is centered. Rotate scale so that number of degrees specified in opposite pointer. Place cam follower on second step of cam next to high step. Close choke by pushing upward on choke coil lever. To adjust, bend tang on fast idle cam until bubble is centered. Remove gage.
With slow idle speed correctly adjusted, fully open choke and make sure fast idle cam follower is off steps of cam. With dashpot fully compressed, adjust for 1/16″ clearance between dashpot plunger and throttle lever.
Remove the air cleaner and check to see that choke valve and rod more freely. Disconnect choke rod at choke lever. Check choke adjustment by holding choke valve closed and position rod so that it contacts stop. If necessary, adjust rod length by bending rod at offset. Bend must be such that rod enters choke lever hole freely and squarely. Connect rod at choke lever and install air cleaner.
Air Injection Reactor (A.I.R.) Description and Operation
The A.I.R. system is used to burn the unburned portion of the exhaust gases to reduce its hydrocarbon and carbon monoxide content. The system forces compressed air into the exhaust manifold where it mixes with the hot exhaust gases. The hot exhaust gases contain unburned particles that complete their combustion when the addition air is supplied.
The system consists of: An air pump, diverter valve, check valve(s), AIR pipe assemblies and connecting hoses and fittings. Carburetors and distributors for AIR engines are made to be used with the system and should not be replaced with components intended for use with engines that do not have the system.
The air pump is a two-vane pump which compresses fresh filtered air and injects it into the exhaust manifold. The pump consists of: a housing, centrifugal filter, set of vanes that rotate about the centerline of pump housing bore, the rotor, and the seals for the vanes. The centrifugal filter is replaced by first removing the drive belt and pump pulley; then pulling filter off with pliers. Care should be taken to prevent fragments from entering the air intake hole. NOTE: A new filter may squeal when first put into operation. Additionally, GREAT CARE should be taken in working on the compressor as the aluminum used is quite soft and thin.
The air pump is operating satisfactorily when the air flow from it increases as engine speed increases.
The air hoses should be replaced only with hoses which are designed for AIR system use, as no other type hoses can withstand the high temperature.
Check and Adjust Dwell
Start engine then check ignition dwell. With engine running at idle, raise the adjustment screw window and insert an Allen wrench in the socket of the adjusting screw. Turn the adjusting screw as required until a dwell reading of thirty degrees is obtained. A two degree variation is allowable for wear. Close access cover fully to prevent the entry of dirt into the distributor. If a dwell meter is not available, turn adjusting screw clockwise until engine starts to misfire, then turn screw one-half turn in the opposite direction to complete adjustment.
Slowly accelerate engine to 1500 rpm and note dwell reading. Return engine to idle and note dwell reading. If dwell variation exceeds specifications, check for worn distributor shaft, worn distributor shaft bushing or loose breaker plate.
Remove distributor cap, clean cap and inspect for cracks, carbon tracks and burned or corroded terminals. Replace cap where necessary. Clean rotor and inspect for damage or deterioration. Replace rotor where necessary. Replace brittle, oil soaked or damaged spark plug wires. Install all wires to proper spark plug. Proper positioning of spark plug wires in supports is important to prevent cross-firing. Tighten all ignition system connections. Replace or repair any wires that are frayed, loose or damaged.
Disconnect the distributor spark advance hose and plug the vacuum source opening. Start engine and run at idle speed. Aim timing light at timing tab. The markings on the tabs are in two degree increments (the greatest number of markings on the “A” side of the “Q”). The “O” marking is TDC (Top Dead Center) and the BTDC settings fall on the “A” (advance) side of the “O”. Adjust the timing by loosening the distributor clamp and rotating the distributor body as required, then tighten the clamp, and recheck timing. Stop engine and remove timing light and reconnect the spark advance hose.
Inspect each plug individually for badly worn electrodes, glazed, broken or blistered porcelains and replace plugs where necessary. Clean serviceable spark plugs thoroughly, using an abrasive-type cleaner such as sand blast. File the center electrode flat. Inspect each spark plug for make and heat range. All plugs must be of the same make and number. Adjust spark plug gaps to .035 in. using a round feeler gauge. If available, test plugs with a spark plug tester. Inspect spark plug hole threads and clean before installing plugs. Install spark plugs with new gaskets and torque to specifications. Connect spark plug wiring.
Transistorized Distributor (H.E.I. System)
There are no moving parts in the ignition pulse amplifier, and the distributor shaft and bushings have permanent type lubrication, therefore no periodic maintenance is required for the magnetic pulse ignition system.
Distributor (Breaker Point System)
Check the distributor centrifugal advance mechanisms by turning the distributor rotor in a clockwise direction as far as possible, then releasing the rotor to see if the springs return it to its retarded position. If the rotor does not return readily, the distributor must be disassembled and the cause of the trouble corrected.
Check to see that the vacuum spark control operates freely by turning the movable breaker plate counter-clockwise to see if the spring returns to its retarded position. Any stiffness in the operation of the spark control will affect the ignition timing. Correct any interference or binding condition noted.
Examine distributor points and clean or replace if necessary. Contact points with an overall gray color and only slight roughness or pitting need not be replaced. Dirty points should be cleaned with a clean point file. Use only a few strokes of a clean, fine-cut contact file. The file should not be used on other metals and should not be allowed to become greasy or dirty. Never use emery cloth or sandpaper to clean contact points since particles will embed and cause arcing and rapid burning of points. Do not attempt to remove all roughness nor dress the point surfaces down smooth. Merely remove scale or dirt. Clean cam lobe with cleaning solvent, and rotate cam lubricator wick end (or one-hundred-eighty degrees as applicable). Replace points that are burned or badly pitted.
Where prematurely burned or badly pitted points are encountered, the ignition system and engine should be checked to determine the cause of trouble so that it can be eliminated. Unless the condition causing point burning or pitting is corrected, new points will provide no better service than the old points.
Check point alignment then adjust distributor contact point gap to .019″ (new points) or .016″ (used points). Breaker arm rubbing block must be on high point of lobe during adjustment. If contact points have been in service, they should be cleaned with a point file before adjusting with a feeler gauge.
Check distributor point spring tension (contact point pressure) with a spring gauge hooked to breaker lever at the contact and pull exerted at 90 degrees to the breaker lever. The points should be closed (cam follower between lobes) and the reading taken just as the points separate. Spring tension should be 19-23 ounces. If not within limits, replace. Excessive point pressure will cause excessive wear on the points, cam and rubber block. Weak point pressure permits bouncing or chattering, resulting in arcing and burning of the points and an ignition miss at high speed.
Install rotor and distributor cap. Press all wires firmly into cap towers.
Battery and Battery Cables
The top of the battery should be clean and the battery hold-down properly tightened. Particular care should be taken to see that the top of the battery is kept clean of acid film and dirt. When cleaning batteries, wash first with a dilute ammonia based or soda solution to neutralize any acid present and then flush off with clean water. Keep vent plugs tight so that the neutralizing solution does not enter the cell. The hold-down bolts should be kept tight enough to prevent the batter from shaking around in its holder, but they should onto be tightened to the point where the battery case will be placed under a severe strain.
To ensure good contact, the battery cables should be tight on the battery posts. Oil battery terminal felt washer. If the battery posts or cable terminals are corroded, the cables should be cleaned separately with a soda solution and wire brush. After cleaning and before installing clamps, apply a thin coating of a petrolatum to the posts and cable clamps to help slow corrosion.
If the battery has remain undercharged, check for loose or defective fan belt, defective alternator, high resistance in the charging circuit, oxidized regulator contact points, or a low voltage setting. If the battery has been using too much water, the voltage output is too high.
Inspect for deteriorated or plugged hoses. Inspect all hose connections. On engines with closed element air cleaners, inspect crankcase ventilation filter and replace if necessary. On engines with open element air cleaners, remove flame arrestor and wash in solvent then dry with compressed air.
Check the brake fluid regularly, for as the brake pads wear the level will drop rapidly. It should be replenished only with the recommended fluid. Check disc brake assemblies to see if they are wet; it would indicate a leaking cylinder.
Disc brakes do not need periodic adjustments; they are self adjusting. The pads should be replaced when the friction material gets down to 1/16″. This is when the groove in the center of the pad is gone. Check by removing wheel and looking directly into caliper.
Parking Brake (1977-1979)
Raise the vehicle and remove the rear wheels. Loosen the equalizer check nuts until the levers move freely to the “off” position with slack in the cables. Turn the disc until the adjusting screw is visible through the hole in the disc. Insert a screwdriver and tighten the adjusting screw by moving the screwdriver handle upward. Adjust both sides. Tighten until the disc will not move, then back off six to eight notches. Install the wheels and place the brake handle in the applied position – 13 notches. Tighten the check nuts until an 80 pound pull is required to pull the handle into the fourteenth notch. Torque the check nuts to70in. lbs. With the hand brake off, there should be no dragon either of the rear wheels.
Clutch Pedal Play
Check clutch action by holding pedal 1/2″ from floor and move shift lever between first and reverse several times, with engine running. If shift is not smooth adjust clutch. Free play with pedal released is approx. 1-1/4″ to 2″ and 2″ to 2-1/2″ for heavy duty.
At clutch lever near firewall remove clutch return spring. To decrease clutch pedal free play remove clutch pedal return spring and loosen lower nut on clutch pedal rod; take up play with upper nut. Continue until proper play is obtained, then securely tighten top nut and replace spring. To increase pedal play work nuts in opposite sequence.
Clutch Adjustment (1975-1982)
Disconnect the clutch return spring at the cross shaft. Push the clutch lever until the pedal is against the rubber stop under the dash. Loosen the two shaft locknuts and push the shaft until the throwout bearing just touches the pressure plate spring. Tighten the top locknut toward the swivel until the distance between it and the swivel is 0.4″. Tighten the bottom locknut against the swivel. The pedal free travel should not be 1-1/2″.
Disconnect control linkage at carburetor throttle lever. Hold carburetor throttle lever in wide position. Pull control linkage to wide open position. (On vehicles equipped with automatic transmission, pull through detent.) Adjust control linkage to freely enter hole in carburetor throttle lever. Connect control linkage at throttle lever.
Throttle Linkage Adjustment (Powerglide)
Remove air cleaner, disconnect accelerator linkage at carburetor. Disconnect accelerator return and trans. road return springs. Pull upper rod forward until transmission is through detent. Open carburetor wide open, at which point ball stud must contact end of slot in upper rod. Adjust swivel on end of rod if necessary.
Pull detent switch driver to rear until hole in switch body lines up with hole in driver. Insert a 3/16″ pin through hole to depth of 1/8″, and loosen mounting bolts. Open throttle fully and move switch forward until lever touches accelerator lever. Tighten mounting bolt and remove pin.
EGR Valve Check
A rough idling engine may be caused by a malfunction of the valve. Check by pinching vacuum hose to carburetor with engine idling. If idling smooths out, the valve should be removed for cleaning or replacement if something appears to be broken.
Lubrication Engine Oil
The car should be standing on level ground and the oil level checked with the dipstick. Withdraw the dipstick, wipe it with a clean rag, replace and withdraw again. The mark made by the oil on the lower end of the dipstick will indicate the oil level. If necessary, oil should be added through the filler cap. Never let the oil level fall so low that it does not show at all on the dipstick. If in doubt, it is better to have a bit too much oil than too little. Never mix oils of different brands, the additives may not be compatible.
Engine Oil Drain and Replacement
Place a pan under the oil pan drain plug and remove plug. Be sure pan is of a large enough capacity to hold the oil. Move pan under filter and remove filter by turning if counterclockwise. Clean gasket surface of cylinder block. Coat gasket of new filter with engine oil. Thread filter into adapter. Tighten securely by hand. Do not overtighten filter. Remove drop pan.
Remove drain pan. Inspect oil pan drain plug gasket and replace if broken, cracked, or distorted. Install drain plug and tighten. Fill crankcase to required level with recommended oil. Operate engine at fast idle and check for oil leakage.
When changing oil filter, add one additional quart.
Check fluid level with engine idling, transmission in neutral and engine at normal operating temperature. Add fluid as needed to bring level to mark. Do not overfill.
Every 12,000 miles or sooner, depending on service, remove fluid from sump and add new fluid. Operate transmission and check fluid level. Every 24,000 miles the transmission sump strainer of the Turbo Hydra-Matic transmission should be replaced.
Raise car on lift, clean dirt and grease from area around the filler plug. Plug is located on side of transmission case. Remove plug and place finger tip inside hole. The oil should be just about level with the bottom edge of the hole. Add oil as needed, using a plastic syringe.
Change cam lubricator end for end at 12,000 mile intervals. Replace at 24,000 mile intervals.
With the car standing level, clean dirt and grease from area around filler plug. Remove plug and place finger tip inside hole. The oil should be just about level with the bottom edge of the hole. Add oil, with a plastic syringe, as needed.
1977 Corvette Dealers Sales Brochure
Download this 1977 Corvette Dealers Sales Brochure for a quick look at the features of the car.