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During the 1980s, the C/K trucks saw additional revisions to the powertrain line, shifting towards more advanced engine designs. As part of the 1981 model revision, the 454 V8 became available on K-series trucks for the first time, replacing the 400 V8 entirely. To improve its fuel efficiency, the 305 V8 received electronic spark control (in markets outside of California); the 350 became the standard V8 for California.In line with the Chevrolet Bonanza, GMC offered the Royal Sierra appearance package, coupled with the Sierra Grande and High Sierra; in Canada, GMC offered several Sierra Wrangler exterior appearance packages (prior to the use of the name by Jeep).During the 1992 report, a third-generation C/K caught fire in an 30 MPH side-impact test collision. Following subsequent investigation, the speed of the collision was found to be higher (approximately 40 MPH). After finding the charred wreckage of the tested GM pickups, GM investigators Failure Analysis Associates (FaAA, now Exponent) examined the fuel tanks of the vehicles; after X-ray examination, it was discovered that none of them had ruptured after collision. It was also found that to stage the explosion, NBC experts used model-rocket engines coupled with a leaking fuel cap to stage the explosion. After reviewing the video itself, smoke was found erupting underneath the truck a few frames before the collision; additionally, the subsequent fire lasted for only 15 seconds. The Blazer/Jimmy shared the same external design changes as Fleetside/Wideside pickup trucks. For 1976, the configuration of the body was updated, changing from a fully open convertible to a half-cab design; while the rear top remained removable, rollover protection improved for front-seat passengers. While design changes were largely evolutionary (to preserve sales of the highly profitable model line), the body of the C/K trucks was completely reshaped forward of the windshield. While retaining a distinct shoulder line wrapping around the body, the front fenders were reshaped to include a lowered hoodline (relocating the side marker lights); the windshield wipers were now exposed.Towing and payload capacity ratings for Rounded Line C/K-Series pickups varied (dependent on configuration). Factors such as engine and transmission combination, differential gear ratio, curb weight, and whether the pickup was two-wheel drive or four-wheel drive decided how much the pickup could safely tow or haul.

In April 1994, General Motors rejected a government request to issue a recall for all 1973-1987 C/K pickup trucks, claiming that it would involve over 6 million vehicles at a cost of over $1 billion. As of today, such a recall would have been the third-largest ever (in terms of size). On October 17, 1994, U.S. Transportation Secretary Federico F. Pena announced that a two-year investigation had found that the trucks posed a fire hazard; federal officials estimated that 150 persons may have died in preventable fiery crashes. In its investigation, the government found that the 1973-1987 C/K trucks were at least 2.5 times more likely to produce a fire-related fatality from a side-impact crash than a comparable Ford or Dodge pickup truck. As most recalls are issued by the manufacturer, government-issued recalls are fairly rare (only 8 had been issued at the time of the investigation). In the 1980s, GM had blocked an effort in court for a recall over a suspected brake problem of the model line. In response, the government clarified that vehicles sold in the United States must meet the National Traffic and Motor Vehicle Safety Act; along with meeting safety standards at the time of production, their production is also required to allow them to operate them safely under real conditions. Soft touch materials were used throughout the passenger cabin, such as the dashboard, doors (arm rests), steering wheel, and shift levers. Subtle grained interior panels and bright metal work was used on the inside with high-quality materials also used on the outside, like chrome, aluminum, and polished stainless steel, particularly on top-of-the-line luxury Silverado or Sierra Classic trim levels. Custom Vinyl vinyl or soft Custom Cloth cloth and velour seating surfaces were used along with fabric headliners, door inserts, and plush carpeting, depending on the trim level. Upper class trim levels also used acoustic deadening materials for quieter ride comfort. From model years 1973 to 1977, chestnut wood grain inserts were used on the dashboard and doors for further visual enhancement. The wood grain inserts were replaced by bright brushed aluminum inserts for model years 1978 to 1987. A Delco AM/FM audio sound system and an all-season climate control system were optional extras.During the 1970s, the model range underwent several revisions to its powertrain line. For 1975, a 400 cubic-inch V8 was introduced as the largest engine option for K-series trucks, slotted above the 350; in another change, catalytic converters were fitted to all trucks under 6000 lbs GVWR. For 1977, a 305 cubic-inch V8 was introduced for C-series half-ton trucks, expanding the engine range to six. For 1978, General Motors became the first major American manufacturer to market a light-duty truck with a diesel engine, offering a 350 cubic inch Oldsmobile diesel V8 as an option for half-ton C-series trucks; the engine also marked the launch of the Oldsmobile diesel engine family.

For 1975, Chevrolet revised its C/K trim lines, with two making an appearance for the first time. The Scottsdale was slotted above the Custom Deluxe (which replaced the Custom as the base trim) and the Silverado replaced the Cheyenne Super as the flagship trim. For 1982, Chevrolet discontinued the Cheyenne trim line, largely consolidating it with the Silverado. The Cheyenne name returned for 1988, serving as the base trim of the fourth-generation C/K, alongside the R/V pickup and Suburban.As it entered production for 1973, the third-generation C/K-Series marked multiple safety advancements concerning full-size pickups. The model line was the first full-size pickup produced with a passenger-side sideview mirror as standard equipment. While in use in GM cars since 1967, the Rounded-Line pickups were the first full-size trucks produced with an energy-absorbing collapsible steering column.

For 1979, the front fascia underwent a minor facelift. While sharing the same stamping as before, the vertical bars were painted dark gray; chrome trim incorporated the turn signal lenses, giving chrome to nearly the entire front fascia. In line with Fleetside/Wideside trucks, Stepside/Fenderside and Big Dooley trucks replace exposed fuel caps with fuel-tank doors.Third-generation C/K pickups have a high tensile strength carbon steel ladder type frame with a “drop center” design. The steering system is a variable-ratio recirculating ball steering gear; hydraulic power assist was optional.

A new Eaton Automatic Differential Lock (ADL) was introduced in 1973 as an optional extra on the Rounded-Line C/K-Series pickups, for the rear hypoid differential. The new automatic locking differential was offered under the G86 code, replacing the Eaton NoSpin differential, and eventually replacing the old Positraction limited-slip differential in 1974, at which point it assumed the G80 code. The Eaton ADL featured intelligent differential control via an internal governor which monitored vehicle speed and wheel slip to know when to automatically lock and could lockup 100 percent at or below 20 mph (32 km/h) increasing tractive effort. The differential lock would unlock and deactivate at speeds above 20 mph for safety reasons, such as the vehicle being on dry pavement.The gas tanks leaked in at least two crash tests performed by GM around the time the trucks were first sold in 1972. The federal report also stated that 50 MPH crash tests performed in the early 1980s “clearly demonstrated” the tanks were susceptible to puncturing.

Heavy-duty towing equipment was available for both C and K-Series pickups, such as the Trailering Special package (included power steering, uprated battery, and uprated generator), 7-pin trailer electrics connector, heavy-duty engine oil cooler, heavy-duty transmission oil cooler, and a weight distributing trailer hitch. An optional Elimipitch camper was made available for the Big Dooley.The third-generation C/K marked several firsts to the model line. Alongside the two-door regular cab, a four-door crew cab made its debut. While trailing Dodge, Ford, and International by a decade in bringing a crew cab pickup truck to production, the C/K crew cab shared its body construction with the Suburban wagon (giving it four passenger doors for the first time). Derived from the C/K chassis cab, “Big Dooley” was the first factory-produced dual rear-wheel pickup, sold only as a one-ton truck.

In line with Chevrolet, GMC introduced four trim levels for its third-generation C/K pickup trucks. Custom served as a base trim (the only name in common with Chevrolet) below Super Custom. As a counterpart of the Cheyenne and Cheyenne Super, GMC offered the Sierra and Sierra Grande, respectively. For 1975, in a revision of its C/K line, all GMC pickups became Sierras, with the Sierra becoming the base trim, followed by the Sierra Grande, High Sierra, and Sierra Classic.On November 17, 1992, Dateline NBC aired an investigative report titled “Waiting to Explode”. Coinciding with federal investigations into the model line, Dateline focused on allegations on the third-generation C/K trucks exploding in side-impact collisions due to the design of the fuel tanks. As a central part of the episode, Dateline showed sample footage of a low-speed accident in which the fuel tank exploded. In what would become a controversy of its own, the program did not disclose that the accident was staged to optimize an explosion.

In 1993 the bad publicity generated by the Dateline story spawned several class action lawsuits. In addition GM was sued more than 100 times in lawsuits brought by individuals who were burned in GM trucks. Nearly all of those cases were settled out of court. In 1993, a Georgia jury awarded more than $105 million, including $101 million in punitive damages, to the parents of a 17 year old named Shannon Moseley who burned to death. The verdict was later overturned by an appeals court and the case settled before it could be re-tried.Chevrolet marketed its C/K pickups under four trim levels for 1973, carried over from the previous generation. The standard trim was the Custom, slotted below the Custom Deluxe; the top two trims were the Cheyenne and Cheyenne Super. On all pickup trucks, the model line was fitted with front self-adjusting disc brakes and rear finned drum brakes. Power-assisted brakes were optional, with either four-wheel hydraulic Hydra-Boost or Vacuum-Boost power assist. The Custom was a basic vehicle with minimal exterior and interior trim, with the Custom Deluxe upgrading by adding color-keyed upholstery and interior trim and additional chrome trim. Intended for personal use, the Cheyenne and Cheyenne Super added carpeting, a headliner, and additional sound insulation; the Super offered the most interior trim on the door panels.Fatality figures vary wildly. A study by Failure Analysis Associates (now Exponent, Inc.) found 155 fatalities in these GM trucks between 1972 and 1989 involving both side impact and fire. The Center for Auto Safety, Ralph Nader’s lobbying group, claims “over 1,800 fatalities” between 1973 and 2000 involving both side impact and fire.

As part of the body facelift, the 1981 C/K pickup trucks received new grilles and redesigned front bumpers; Chevrolet grilles were split in the middle by a silver/black bar, with GMC grilles divided into ten squares. Square headlights became standard for the first time; base-trim trucks were fitted with two headlights and upper-trim trucks received four headlights (relocating the turn signal lenses to the front bumper). For the first time since 1975, fender badging was revised, with scripted badging replaced by block lettering (a design that would last through 1987). The interior underwent its own revision, receiving updates to the seats, door panels, and dashboard.A properly equipped C-Series half-ton class pickup could tow up to 8,000 lbs (4 tons) of braked trailer, while a properly equipped C-Series three quarter-ton or one-ton class pickup could tow up to 12,000 lbs (6 tons) of braked trailer. Adding four-wheel drive reduced towing capability due to increased curb weight, which resulted from additional driveline components (transfer case, front axle, front differential, front propeller shaft, and so on) needed to facilitate four-wheel drive. A properly equipped K-Series half-ton or three quarter-ton class pickup could tow up to 6,500 lbs (3.25 tons) of braked trailer; a properly equipped K-Series one-ton class pickup could tow 500 lbs more, up to 7,000 lbs (3.5 tons) of braked trailer.

For 1980, diesel engines made their return with the introduction of the Detroit Diesel 8.2 L “Fuel Pincher” V8. The same year, GM introduced the Chevrolet Kodiak/GMC TopKick. Largely developed to accommodate the Caterpillar 3208 diesel V8 engine, the Kodiak was slotted between the medium C/K and the heavy-duty Bruin/Brigadier conventional; it received a larger, squared-off hood and grille, which required raising the cab several inches upward.For 1982, GMC followed suit with Chevrolet, downsizing to a three-trim line; the Sierra Grande was dropped. For the fourth-generation C/K, GMC dropped the external C/K nomenclature, with all pickup trucks becoming Sierras (C/K remaining in use for internal model codes). For 1989, GMC adopted the trim nomenclature of the fourth-generation C/K for the R/V series pickups.

The four-door crew cab was offered in two configurations. Along with the standard six-seat (badged as “3+3”) crew cab, a “Bonus Cab” configuration was offered, deleting the rear seat of the crew cab (effectively a 3-seat truck with a large internal storage area).For 1977, a K30 (four-wheel drive, full one-ton chassis) was added to the lineup, and a Dana 60 was used for the front axle. For the 1980 model year, full-time four-wheel drive was discontinued on K-Series, leaving only conventional four-wheel drive.

Regardless of any increased risk of fire, the GM trucks had safety records in side-impact crashes statistically indistinguishable from their Ford and Dodge counterparts. The sidesaddle fuel tanks themselves were found to have a robust design highly resistant to crushing or crumpling from a side impact. Trucks equipped with these tanks met and exceeded the requirements of Federal Motor Vehicle Safety Standard No. 301. Studies showed that it would take about 4,000 side-impact crashes with such a truck to get one with fire, major injury, or fatality.

After an 18-year production run, 1991 marked the final year for the “Rounded Line” truck series. After trailing the rest of the C/K series for nearly five years, one-ton crew cab pickups, the Suburban SUVs, and the K5 Blazer/V-Jimmy all adopted the GMT400 architecture. To end nameplate confusion with its compact SUVs, GMC renamed the Jimmy as the GMC Yukon for 1992, with the Chevrolet K5 Blazer becoming the Chevrolet Tahoe for 1995.

At its 1973 launch, the Rounded-Line pickup trucks were offered with five different engines. A 250 cubic-inch inline-six was standard, with the option of a 292 cubic-inch inline-6, a 307 cubic-inch V8, a 350 cubic-inch V8, and a 454 cubic-inch V8. Available only in two-wheel drive C-series trucks, the 454 replaced the 402 cubic-inch “396” V8; the 307 was offered only for 1973.For 1976, outboard seats received 3-point (lap-and shoulder) safety belts with emergency locking retractors; a center lap safety belt was used, with slack adjustment. For 1977, Ford and Dodge would follow suit, adding the same seat belt design to their full-size trucks.During the 1970s and early 1980s, Chevrolet marketed the Bonanza appearance package coupled with the Scottsdale (and later Silverado) trim, adding upgrades such as interior carpeting.For 1980, the front fascia underwent an additional update. While GMC trucks carried over the same grille from 1979, Chevrolet trucks received an all-new grille (its first completely new design since 1974). Square headlights made their appearance for the first time on Silverado-trim models; lower-trim vehicles used a combination of the 1980 grille and the 1979 (round) headlight surround.

In Brazil, General Motors do Brasil produced the Rounded-Line series as the 10/20 series. Introduced in 1985, the model line replaced the locally produced C10 (derived from the first-generation 1964 C/K). The model line was marketed under three model series, designated by fuel (A=ethanol, C=gasoline, D=diesel). Sharing primarily its cab structure with its American counterpart, the 10/20 was produced with its own front fascia (sharing its headlights with the Chevrolet Opala). Shared with the Opala, a 135 hp 4.1L inline-6 (discontinued in the United States in 1984) was used for gasoline and ethanol versions; an 87 hp 3.9L Perkins inline-4 diesel was offered. For 1986, a “double cab” was introduced, sharing the 4-door crew cab of its North American counterpart. During the early 1990s, the 10/20 series underwent several mechanical updates and was produced by GM do Brasil through 1997, when it was replaced by the GMT400-derived Silverado produced in Argentina. On February 8, 1993, after announcing its anti-defamation/libel against NBC, GM conducted a highly publicized point-by-point rebuttal in the Product Exhibit Hall of the General Motors Building in Detroit that lasted nearly two hours. On February 10, 1993, GM settled with NBC, resulting in multiple NBC personnel losing their jobs. Alongside the full-size pickup range, the “Rounded Line” C/K series also included a variety of other vehicles. The C/K (and R/V) chassis and body were used for the Chevrolet/GMC Suburban, the Chevrolet K5 Blazer/GMC Jimmy, and multiple GM commercial trucks for the 1970s and the 1980s.

For the 1987 model year, GM renamed the C/K series as the R/V series. Largely intended to distinguish the C/K series from its GMT 400 successor (which would be produced alongside it), “R” was used for two-wheel drive and “V” for four-wheel drive; the nomenclature change was also applied to the vehicle identification number (VIN). The 1987 R/V models continued production at Janesville, St. Louis, and Flint; the new 1988 GMT400 trucks entered production December 8, 1986 at Pontiac East, Oshawa, and the new Fort Wayne plant.For 1989, all R/V pickup trucks (and related SUVs) underwent their most visible facelift since 1981. While retaining the same fenders and hood from 1981 to 1988, the grille was redesigned for a nearly flush appearance, with much of the trim painted black. For both Chevrolet and GMC, two versions were designed; a twin headlight version was offered (for base trims) and a quad headlight version for all upgraded trims (and non-fleet Blazers and Suburbans). In another nomenclature change, the R/V series adopted the 2500/3500 series payload series for both GMC and Chevrolet.For 1973, the General Motors medium-duty truck range (Class 5-7) underwent a redesign. Slotted below the Class 7-8 H/J and C/M heavy conventional trucks (designed by GMC), the Chevrolet-designed vehicles shared their cab with the Rounded-Line series. With the exception of the steering column and gear shifter, the model lines shared much of their interior.In early 1987, GM introduced the 1988 fourth-generation C/K to replace the Rounded Line generation, with the company beginning a multi-year transition between the two generations. To eliminate model overlap, the Rounded Line C/K was renamed the R/V series, which remained as a basis for full-size SUVs and heavier-duty pickup trucks. After an 18-year production run (exceeded in longevity by the Dodge D/W-series/Ram pickup and the Jeep Gladiator/Pickup), the Rounded Line generation was retired after the 1991 model year.The largely rectangular front fascia of the Rounded Line trucks (leading to the colloquial “Square-body” and “Box-body” nicknames from the media and public) led to many departures from previous generations of C/K truck design. As with GM cars, the hood line of the C/K trucks was faired into the front fenders (replacing the clamshell design). While a wraparound windshield (from the Task Force trucks) was never under consideration, a more widely curved windshield (along with curved windshield glass) was added to the cab. To visually integrate the cab with the pickup bed, a shoulder line wrapped from fender to fender around the vehicle (on Fleetside/Wideside beds). To further reduce noise, the mast antenna was removed and was embedded within the windshield glass. The interior of the C/K trucks underwent major functional changes, replacing the completely flat dashboard with a sedan-style design, centering controls and gauges closer to the driver.

For 1973, General Motors introduced the seventh generation of the Suburban using the Rounded Line truck chassis. Marketed at the time as a truck-based station wagon, the Suburban was marketed by both Chevrolet and GMC under the same nameplate. Far larger than the Jeep Wagoneer (by nearly 3 feet), the Chevrolet Suburban competed largely against its GMC namesake following the 1975 discontinuation of the International Travelall.

The Rounded Line trucks underwent a mid-cycle redesign for the 1981 model year. Largely in response to the 1979 energy crisis, GM engineers again turned to wind tunnels to further reduce areas that hindered air flow and caused drag, along with shedding nearly 300 pounds of curb weight from the model line.

Offered as standard equipment for K-series trucks with inline-6 engines, the conventional four-wheel drive system was equipped with a two-speed New Process 205 transfer case with four drive modes: Two High, Four High, Neutral, and Four Low. Two High gave a 0:100 torque split, while Four High yielded a locked 50:50 torque split. Four Low applied reduction gearing. The front and rear propeller shafts were locked at all times in Four High and Four Low. Neutral allowed for flat towing, or use of the power take off (PTO).For 1977, the front fascia underwent a second revision, with both Chevrolet and GMC receiving larger-segment grille designs. On all trims, the interior received revised door panels (covering a larger portion of the doors). As an option, the C/K offered power windows and power door locks for the first time. The 1978 model year was distinguished by a redesigned fuel-filler door (replacing the exposed fuel cap); woodgrain dash trim (for the Cheyenne and Silverado) was replaced by brushed-aluminum trim. Other safety features included soft-padded interior panels for appearance and safety, 3,329 square inches of tempered and laminated safety glass, prismatic rearview mirror, six turn-signal indicator lamps with asymmetrical flash, four-way hazard function, and lane departure function. During the development of the Rounded-Line generation of pickup trucks in the late 1960s, the fuel tank was relocated from inside the cab to the outboard side of the right frame rail (if an auxiliary fuel tank was specified, both frame rails). Commonly referred to as a sidesaddle configuration, the decision was largely made in the interest of reducing in-cab exposure to fuel vapors (and to carry more fuel). After the 1991 discontinuation of the model line, the design underwent both media and government scrutiny related to potential fire hazards of the configuration. Sevel Argentina S.A. built the Chevrolet C10 in its Córdoba plant from 1985 to 1991. The gasoline version used the Chevy 250 CID engine (4,093 cc) familiar to most Latin American markets, producing 130 hp. Because of Sevel being a subsidiary of Peugeot, the C10 was also available with a 70 hp Indénor XD2 2,304 cc diesel engine, perhaps best known in the US from the Peugeot 504. For 1973 and 1974, the C/K model line was given a recessed front grille with orange turn signals (GMC grilles were divided in thirds). For 1974, door-mounted drip moldings were added as an option (becoming standard in 1975).For 1992, the second-generation Blazer/Jimmy were replaced in a transition to the GMT400 architecture; the V-Jimmy was renamed the GMC Yukon (with the K5 Blazer later becoming the Tahoe). In a major change, the removable hardtop design was discontinued (effectively making the model line a short-wheelbase version of the Suburban).

For 1983, the front fascia underwent a minor revision. Along with dropping the two-headlight configuration, Chevrolet and GMC received revised grilles (including the turn signals behind them). For 1984, the two-headlamp configuration returned for base-trim vehicles (relocating the turn signals from the grille to the headlamp surround).Across its 18-year production, the third-generation C/K model line underwent several minor revisions. For 1981, the trucks underwent a mid-cycle revision. To accommodate the 1987 calendar-year introduction of the fourth-generation C/K for the 1988 model year, GM re-designated the third-generation C/K as the R/V series for 1987. Sold alongside its successor, the R/V series was produced through the 1991 model year.

For 1982, the front fascia underwent a trim revision, with a chrome bumper and a chrome-trim front grille becoming standard equipment. In a functional change, 3⁄4-ton and 1-ton trucks switched from 16.5-inch to 16-inch wheels (to adopt more commercially available tires). To denote the introduction of a 6.2 L diesel V8, vehicles with the diesel engine received fender and tailgate badging denoting the diesel engine.From 1972 to 1991, General Motors produced the Rounded Line C/K (later R/V) series in multiple facilities across the United States and Canada. In South America, the model line was produced in Argentina and Brazil, ending in 1997.

For 1976, engine displacement decals were removed from the grille; a voltage gauge replaced the ammeter in the instrument panel. In another change, the simulated woodgrain exterior trim is discontinued (woodgrain interior trim remains in use for door panels and the dashboard on upper-trim models). The optional wheelcovers were revised; a flatter design was introduced for both Chevrolet and GMC with black-painted accents.

After 1989 production, GM replaced the medium-duty C/K and the Kodiak/TopKick with a single medium-duty truck line (codenamed GMT530), using the GMT400 truck cab and adopting the Kodiak/TopKick name.

The wheelbase length was extended to 117.5 in (2,985 mm) for short wheelbase pickups, and 131.5 in (3,340 mm) for long wheelbase pickups. For 1-ton pickups, a dual rear-wheel option (called “Big Dooley”) was introduced, alongside a four-door crew-cab; the latter used a 164.5-inch wheelbase on either single or dual rear wheels.For 1975, the front fascia underwent a minor revision, with Chevrolet replacing the recessed grille with a flush-mounted design (appearing brighter in color); GMC introduced a six-segment grille (splitting the 1973–1974 grille in half). The trim lines underwent a major realignment, as Chevrolet introduced the Scottsdale and Silverado trims. In response to extended-cab Ford and Dodge pickups, a C20 four-door pickup with no rear seat is introduced, offering additional storage space.

The Chevrolet Outdoorsman was a special package that offered unique Green, Gray, Blue, or Gold colors with an Outdoorsman decal set, plus your choice of $500 worth of of name-brand hunting, camping or fishing equipment. The hunting package included a Winchester Model 94 XTR hunting rifle with a Chevrolet Outdoorsman emblem recessed into the stock, while Outdoorsman TV commercials featured NFL player Dick Butkus.For fans of the outdoors, a camper-special square-body model was aimed at heavier, bulkier loads, and it featured the amusingly named Elimi-Pitch Package. The latter included special dampers connecting bed to body and camper to cab, to help calm the truck’s handling in turns. With so much new to offer, is it any surprise that 666,619 C/K trucks were sold this year by Chevrolet? (At press time, GMC sales figures were unavailable.) Canadians weren’t left out in the cold, as GMC offered an Olympic Edition based on the Sierra Grande—a white/red paint job, rally wheels, and a hood ornament with the five-rings Olympics logo. GMC also partnered with Hickey Enterprises to make the Desert Fox. The Fox featured one of the most memorable graphic treatments in the division’s history—a cornucopia of earth-tone stripes laid over a buckskin-colored body. The front guard, roll bar, and wagon-wheel spokes were also painted buckskin. Unsurprisingly, the model has a cult following in the Middle East—the connection was enough for GMC to make a Desert Fox tribute truck in 2017.

The GMC Beau James was a top line Sierra Classic with a blue/silver paint scheme, whitewall tires, “wire-wheel” wheel covers, “Beau James” graphics at the end of the bed, and even a hood ornament with the Beau James logo!The 1973 square body trucks were new from bumper to bumper, with a tougher look than either Dodge’s new, rounder D-series (1972–1980) or the sixth-generation (1973–1979) Ford F-series. But the General’s trucks also benefited from modern computer simulations, long before production, in the interest of increased durability. While the ’73 design was indeed squarish, as the name suggests, it saw wind-tunnel time during development in order to improve aerodynamics and lower side air turbulence: corners were rounded, side windows were curved, the body sides featured prominent curves from front to back, and the tail lights wrapped around the bed. The angular wheel arches were rounded at both corners to help take the edge off the styling, and compared with its predecessor, the truck featured a radical increase in glass area.

The new frame allowed for a lower cab, which aided in entry and exit. Front spring rates were newly softened, and a front anti-roll bar, a new feature, helped improve both ride and handling. Front disc brakes were also standard. Rear leaf springs were now two-stage progressive, while rear shock mounts were redesigned in order to reduce wheel hop. An energy-absorbing steering column was added to the cab, and the arrival of GM’s infamous “side saddle” fuel tank saw the truck’s fuel move from from inside its cab to outside its frame rails. (That tank design was later featured on Dateline NBC, where the show’s producers rigged a crash test to ensure that a square-body tester would catch fire following an impact. The episode resulted in long court debate and an extraordinary public apology by NBC.)

Sharing the spotlight with GMC big rigs and vans but limited to C/K 20 configurations, the 1977 Sarge model featured forged aluminum wheels, white-letter tires, silver paint with red/orange/yellow stripes, color-matched bed rails, a three-spoke steering wheel wrapped in leather, and a CB radio.A new grille once again greeted buyers, its insert either silver or body color. Large signal lights also appeared below the headlights this year. (If a truck was equipped with the Deluxe Front Appearance Package, which brought quad headlights, the signal lights were mounted within the grille.)

Fleetside models now offered the stepside’s Sport trim package, but only for short-bed configurations. Trucks ordered with bucket seats saw a switch from low-back seats to high-back units, while the 3+3 crew-cab configuration was now available with a rear-seat delete. The change gave an extra 56 cubic feet of storage space in the cab and protected from the elements. GMC was once again the pace truck for the Indy 500, this time with a novel black-to-white fade scheme on the truck’s center, through gray gradient stripes. The front bumper sported a sleek air dam, and the color treatment carried over to the white wagon-wheel wheel spokes. Changes were modest this year—notably a new grille shell that integrated the headlights and turn signals, and a new hood with a raised, plateau-shaped stamping above the grille.A new four-speed (Turbo Hydramatic 700R4) automatic sported a fuel-saving overdrive gear and was available on either of the two small-block V-8s offered, 305 or 350. The transfer case on K30 trucks was now synchronized, allowing activation at up to 25 mph, while power steering was made standard for all K-series models. The heavier duty 20- and 30-series trucks now rode on standard 16-inch wheels.

Whether Chevrolet or GMC, the General’s third-generation, “square-body” trucks were a dramatic departure from the company’s previous efforts. The third-gen models featured squared-off front and rear fascias, subtle body contours honed by wind-tunnel testing, a more accommodating and ergonomic interior, and even an available crew-cab body, a style decades ahead of its time.

Wheelbases on the all-new frame grew from 1972: Short-bed models (six and a half feet of bed length) saw a 2.5-inch bump, to 117.5 inches, and long-bed models (eight feet of bed) gained 4.5 inches, to 131.5. A new Crew Cab option, with two rows of passenger seating, was available for the one-ton trucks, while a “Big Dooley” option gave the square body two pairs of rear wheels for heavy loads. Both Chevrolet and GMC models were available in either a smooth fleetside bed or a stepside one, and wood bed floors with steel skid strips were optional. Fleetside bodies had optional lockable tool compartments on the bottom of the bed.

GMC was again the Indianapolis 500 Pace Truck, and this year had an animated Eagle decal on the bodysides and, in Pontiac Trans Am fashion, a stylized eagle on the hood. The mid-level Cheyenne trim level was deleted. Powertrain changes were significant: the two-barrel, 305 was discontinued, while the Olds 350 diesel was replaced by an all-new, highly regarded 6.2-liter diesel (130 hp, 240 lb-ft) with a three-speed automatic. Diesel models wore prominent “6.2L” badging on the tailgate, a foreshadowing of things to come—the metric system was inbound on American trucks. Offered to GMC truck buyers in California, the California Sundancer was, as its name suggests, a regional special available only in Southern California. Sundancers were painted yellow over charcoal gray, with a gray body stripe and charcoal-colored tube bumpers.The 1981 GMC Indy pace truck replicated the silver/red theme of Buick’s Regal Indy Pace Car. Graphics were far more subtle over the previous year’s pace truck, and items you would expect to be chrome—bumpers, mirrors—were indeed left unpainted. The grille texture changed slightly, a rear cargo light was added, and GM’s new, 4.3-liter V-6 (155 hp) replaced the entry level 250-cube six-cylinder. There were now four unique designs for customers interested in two-tone paint: conventional, special, deluxe, and custom. With that in mind, what follows is a quick, high-level overview of the third-generation C/K truck—be it two-wheel-drive C10/C20/C30, or four-wheel-drive K10/K20. We’ll take a look at model differences year by year but also highlight special editions, so you’ll know which examples are best for you!

The square body’s second year brought modest changes: optional rain gutters above the doors, and the 307 was axed in favor of another 350 V-8 (145 hp) with a two-barrel carburetor. A new full-time four-wheel-drive system was available—albeit only on V-8 models—thanks to a new NP203 transfer case. The square body also gained an all-new interior. The standard wraparound dashboard sported a full complement of gauges. Air-conditioning was available, and buyers could option in an AM or an AM/FM radio, either of which had its antenna cleverly integrated into the windshield. Chevy/GMC offered similar trim levels—Custom, Custom Deluxe/Super Custom (code Z62, with more exterior chrome, chrome wheel covers, and interior features like a dome light, a cigarette lighter, and wood trim), Cheyenne/Sierra (code Z84, with more wood trim, extra insulation, upgraded door panels, etc.), and a Cheyenne Super/Sierra Grande trim level (code YE9, with even more wood trim, thicker carpeting, richer seat fabrics, and optional bucket seating with a center console). Higher trim levels featured bright trim around the body’s side curves, that trim often delineating a two-tone paint treatment. A bolder grille greeted buyers this year, with Chevy’s traditional egg-crate center no longer sunken inside an outer chrome shell. This was the last year that the truck’s grille wore an emblem indicating engine displacement, but behind it sat GM’s new HEI ignition, plus a slew of new intake and emissions equipment, including catalytic converters, if a truck’s equipped GWVR fell under 6001 pounds. The 250-cubic-inch inline six engine now made 105 hp. Models over that 6001-pound GVWR could be ordered with a new, 175-hp, 400-cubic-inch V-8.The GMC Amarillo series by American Coach Corporation was a three-tier upgrade, starting with a cosmetic red/orange/yellow stripe treatment. The GT package added an aerodynamic body kit, a tonneau cover, 10-inch-wide turbine wheels with white letter tires, side exhaust pipes, and a leather-wrapped steering wheel. The top-level Cowboy Cadillac featured everything from the GT but added upgrades worthy of the name: fabric-wrapped panels, 32-ounce carpet and matching floor mats, a high-back “Trucker’s Lounge” seat, and Delco’s top-of-the-line 8-track audio system. With a 454-cubic-inch-V-8 under the hood, performance bettered that of Dodge’s Lil’ Red Express in magazine tests, likely due to the aftermarket wheel/tire combo.

Engine choices included a new 305-cubic-inch V-8 with electronic spark control (49-state only), while the 400-cube V-8 was removed from availability. An new transfer case, the NP208, appeared on K10 and K20 trucks, and all K-series models received automatically locking front hubs and quad front shocks.

While GM’s 1980 sales brochure showcased the C/K trucks’ new square-headlight fascia, the look was limited to top-line Silverado models; round-headlight C/Ks were far more common and remain so today. 1980 also brought a more prominent egg-crate grille and new side-view mirrors, while the deletion of the NP203 transfer case meant the four-wheel-drive system on offer was part-time only.Mimicking the Pontiac Trans Am Indy Pace Car, the GMC Pace Truck wore a black/white/gray paint scheme, with the black cab morphing into the Firebird’s trademark “screaming chicken” hood decal. Forged aluminum wheels with white-letter tires were included, while chrome bumpers/mirrors/grille were instead painted black or white to match the adjacent body panels. A custom front bumper valence was also installed, painted black to match.

Four trim levels were still offered, but both Chevrolet and GMC opted to rename their offerings: Custom Deluxe/Sierra, Scottsdale/Sierra Grande, Cheyenne/High Sierra, and the top-line Silverado/Sierra Classic.Changes were minimal. Rally wheels appeared, and a new Sport model was available on Scottsdale trucks equipped with a stepside bed. Sports paired the aforementioned rally wheels with white-letter tires and color coordinated custom graphics.

Changes were minimal this year—metallic brake pads (front) for 10- and 20- series models, new plastic shields for the side-saddle fuel tanks, and a new steering-column stalk lifted from other GM products.

Engine options were plentiful. Buyers could choose from a 250-cubic-inch in-line six (100 hp), a 292-cube six (120 hp), a 307 V-8(115 or 130 hp), a 350 V-8(155 hp), and the all-new, range-topping 454 big-block V-8 (240 hp). Three- and four-speed manual transmissions were available, plus a three-speed Turbo Hydramatic automatic. Power steering and power brakes were optional.Replicating the successes elsewhere in Chevrolet’s lineup, a new Bonanza special-equipment package was also available on Scottsdales. Bonanzas came with numerous trim and option upgrades in four levels: YG6, YG7, YG8, and YG9.

Chevrolet once again had the Indy 500 Pace Truck this year, but its war paint looked nothing like the custom package gracing the division’s Corvette pace car. The model saw a radical red/white paint job, commemorative lettering in a bold font, a sleek lower valence, color-matched aluminum wheels, and white-letter tires.The GMC Mule was a take on Dodge’s Warlock truck, complete with black paint and gold accents, stake bed planks wearing the original GMC logo, and decals featuring a cartoonish mule rendering.

Lastly there was the Impact ’76, a GMC finished in white with red and blue gradient graphics similar to the 1975 Indy 500 Pace Truck. The key differentiator for the Impact ’76 were the exterior styling accessories (air dam, roof air deflector, mud flaps) from the Motortown Corporation for this special edition.The inclusion of a catalytic converter for models sold in California required modest frame changes. Both Cheyenne and Silverado trim levels received new aluminum-style interior trim instead of wood grain: The Cheyenne used a diamond pattern (dashboard only, aluminum everywhere else) while the Silverado featured brushed aluminum around the gauges, above the glove box, and on the inner door panels. A new grille with more prominent horizontal lines greeted buyers, and the square body’s chrome side trim now featured a gold stripe inside its central channel. In-cabin hood releases became optional, along with power windows, power door locks, a rear window defroster, and intermittent wipers. Presumably only offered in K-series four-wheel drive, the Chevrolet Sno Chaser was advertised as a stylish way to travel in winter climates. There was a unique spoiler that visually extended the B-pillar. Sno Chasers were offered in a red/black paint job with gold graphics, and came with white painted wagon wheels.For buyers of GM’s half-ton and two-wheel-drive trucks, 1978 brought an all-new diesel V-8 (LF9) producing 120 hp, and more important, 220 lb-ft of torque. This was the Oldsmobile 350 diesel, notorious for head-bolt issues. (If you’re looking for one now, a diesel square body that hasn’t been converted to another V-8 is a rare find indeed.)

The GMC pace truck for this year had a more subtle cream, red, and brown paint scheme, to complement the elegant Buick Riviera pace car. Chrome parts remained untouched, while rally wheels and white-letter tires rounded off the package.

For those seeking more utility from a half-ton (C10), or a legal way to avoid complex emissions equipment, Chevy/GMC created the BIG 10/Heavy Half (F44) and placed that name on the trailing edge of the bed. With a GVWR slightly above the emissions threshold (6050 pounds), these trucks offered more performance and lower fleet-management costs (leaded fuel was cheaper and still plentiful) at the expense of more emissions.All of our replacement bed panels are constructed of heavy gauge stamped steel that meets or exceeds the thickness of the original body panel that it’s replacing. The stamping process starts with a 3D scan of an OEM part, which means that these aftermarket panels will be an exact match to the original part’s shape. Since the panels are an exact match, the old panel will need to be cut out so that the new one can be welded in its place.The bed of your truck can haul anything from some camping gear to a load of gravel. You’ve protected the inside of the bed with a slide-in or a spray-on bed liner, and maybe you’ve even had the underside sprayed with undercoating. It’s almost inevitable, though, that road salt and moisture will penetrate these barriers and start to rust the more vulnerable areas, like the lower quarters and wheel arches. Replacing the entire bed can be costly, which is why we sell a wide selection of truck bed repair panels.

Each panel has an EDP coating for additional corrosion protection. The e-coating leaves a black finish that can be scuffed and painted over. For additional rust protection, we offer ZeroRust which is a rust-inhibiting paint. We also offer a selection of undercoating materials as well as DIY spray-on bedliner kits.

This 1973-1987 GM Bedside Rear Corner Section (Fleetside Only) Driver Side fits 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987 Chevy or GMC Pickup Truck.For 1960, C/K pickup trucks were powered by three different engines. A 236 cubic-inline 6 (producing 135 hp) was the standard engine for Chevrolet trucks, with a 305 cubic-inch V6 (producing 150 hp) as standard for GMC trucks; a 283 cubic-inch V8 was optional, producing 160 hp.

For 1964, the cab underwent a major update. While sharing the roof and floor structure, the windshield and A-pillar were redesigned, eliminating the intrusive “dogleg” (requiring new set of door stampings); the redesign also brought a redesign of the dashboard and door panels.The first generation of the C/K series is a range of trucks that was manufactured by General Motors from the 1960 to 1966 model years. Marketed by both the Chevrolet and GMC divisions, the C/K trucks replaced the Task Force generation of trucks. The first General Motors pickup trucks developed on a dedicated truck platform (no longer a derivative of the GM A platform), the C/K series included pickup trucks, chassis-cab trucks, and medium/heavy commercial trucks.

The first-generation C/K formed the basis of the fifth-generation Chevrolet Suburban/GMC Carryall. Competing against the International Travelall and the Jeep Wagoneer, the Suburban became a Chevrolet nameplate (as GMC adopted the Carryall nameplate). Sharing the mechanical upgrades of the C/K truck chassis, the Suburban received factory fitment of four-wheel drive, independent front suspension on rear-wheel drive “C” models, and continued to share body and mechanical commonality with its pickup counterpart.The first-generation C/K trucks were produced from the 1960 to 1966 model years. For 1963, the model line underwent a mechanical revision, with a more substantial update to the body for the 1964 model year.

Produced by multiple sites across the United States and Canada, the model line was also produced in South America. For the 1967 model year, GM introduced a second generation of the C/K, naming it the coral Action-Line series.In line with the Task Force series and its predecessors, the first-generation C/K was offered solely with a two-door cab configuration. The straight-sided Fleetside bed made its return alongside the traditional fendered Stepside bed (GMC Wideside and Fenderside, respectively).