Chevrolet/GMC B-Series

Second generation (1984-1991)
Second generation (1984-1991)
	Retired late 1980s Chevrolet school bus in use as a church bus in Virginia.
Overview
Manufacturer	Chevrolet; GMC
Production	1984-1991
Body and chassis
Related	Chevrolet/GMC C/K medium duty

First generation (1966-1983)
First generation (1966-1983)
	Retired 1977-1983 Chevrolet school bus in use as a shuttle bus in North Carolina.
Overview
Manufacturer	Chevrolet; GMC; GMC Truck & Coach (1966-1970 GMC)
Production	Chevrolet: 1967-1983; GMC: 1966-1970; 1971-1983
Body and chassis
Related	Chevrolet/GMC C/K medium duty ; GMC H6500 (GMC 1966-1970)

Chevrolet/GMC B-series
Chevrolet/GMC B-series
Overview
Type	Bus
Manufacturer	General Motors
Production	1966-2003
Body and chassis
Class	Class 6-7 (Medium/heavy-duty)
Body style	Cowled chassis (conventional-style)
Chronology
Predecessor	Chevrolet/GMC C/K (medium duty)
Successor	none; Blue Bird Vision (indirect)

Last updated March 19, 2019

The Chevrolet and GMC B-series is a series of cowled chassis that were produced by General Motors, primarily fitted with school bus bodies throughout its production. Based on the medium-duty (Class 6-7) trucks produced by the Chevrolet and GMC divisions of General Motors, the B-series was produced in three separate generations; GMC initially produced its own version separate from Chevrolet. Introduced in 1966, the B-series was redesigned in 1984 and 1992 as a 1993 model.

General Motors Company, commonly referred to as General Motors (GM), is an American multinational corporation headquartered in Detroit that designs, manufactures, markets, and distributes vehicles and vehicle parts, and sells financial services, with global headquarters in Detroit's Renaissance Center. It was originally founded by William C. Durant on September 16, 1908 as a holding company. The company is the largest American automobile manufacturer, and one of the world's largest. As of 2018, General Motors is ranked #10 on the Fortune 500 rankings of the largest United States corporations by total revenue.

A school bus is a type of bus owned, leased, contracted to, or operated by a school or school district. It is regularly used to transport students to and from school or school-related activities, but not including a charter bus or transit bus. Various configurations of school buses are used worldwide; the most iconic examples are the yellow school buses of the United States and Canada.

Following the end of a supply agreement with Blue Bird Corporation, effectively leaving General Motors without a body manufacturer with which to supply chassis, the company exited production of full-size bus chassis, producing the later GMT560 solely as a cutaway-cab vehicle. The Blue Bird Vision entered production in 2004, becoming the first conventional-style school bus produced without a second-party chassis.

The Blue Bird Corporation is an American bus manufacturer headquartered in Fort Valley, Georgia. Best known for its production of school buses, the company has also manufactured a wide variety of other bus types, including transit buses, motorhomes, and specialty vehicles such as mobile libraries and mobile police command centers. Currently, Blue Bird concentrates its product lineup on school and activity buses and specialty vehicle derivatives.

The Blue Bird Vision is a bus that is manufactured and marketed by Blue Bird Corporation in North America and exported worldwide. In production since 2003, the Vision became the first cowled-chassis bus built on a proprietary chassis designed and manufactured by the same company. While it is sold primarily in a school bus configuration, the Blue Bird Vision is also offered with various commercial and specialty seating and design configurations.

As of 2017, General Motors remains a supplier of bus chassis for school bus and commercial bus use. Currently, all examples are cutaway van chassis based on the GMT610 architecture (Chevrolet Express/GMC Savana).

Cutaway van chassis are used by second stage manufacturers for a wide range of completed motor vehicles. Especially popular in the United States, they are usually based upon incomplete vans made by manufacturers such as FCA US LLC, Ford Motor Company, and General Motors which are generally equipped with heavier components than most of their complete products. To these incomplete vehicles, a second stage manufacturer adds specific equipment and completes the vehicle. Common applications of this type of vehicle design and manufacturing includes small trucks, school buses, recreational vehicles, minibuses, and ambulances. The term "cutaway" can be somewhat of a misnomer in most of the vehicle's context since it refers to truck bodies for heavy-duty commercial-grade applications sharing a common truck chassis.

Background

Prior to 1966, all medium and heavy-duty trucks of General Motors were derived heavily from the C/K-series trucks (and the Task Force trucks before them). Although using a stronger frame and suspension, much of the bodywork was shared. With the exception of divisionally-produced engines, the Chevrolet and GMC medium-duty trucks were largely identical to one another. Consequently, the conventional-type school bus chassis used for both divisions were largely the same.

The C/K was Chevrolet and full-size pickup truck line from October 1959 until 2000 in the United States and Canada, from 1964 to 2001 in Brazil, and from 1975 to 1982 in Chile. From 1959 to 1987, C/K was also the name of GMC's truck series; it switched to the name Sierra from 1988 to 1999 while sharing the C/K platform. The first Chevrolet pickup truck was introduced in 1924, though in-house designs did not appear until 1930. "C" indicated two-wheel drive and "K" indicated four-wheel drive. The aging C/K light-duty pickup truck was replaced with the Chevrolet Silverado and GMC Sierra names in 1999 in the United States and Canada, and 2001 in Brazil; the Chevrolet Silverado HD and GMC Sierra HD heavy-duty pickup trucks followed. Until this time, the names Silverado and Sierra were used to identify the trim level of the C/K trucks.

The Chevrolet Task Force was Chevrolet's successor to the Advance Design trucks. The Task Force Series ran from late 1955 through 1959. At GMC locations, it was called the Blue Chip Series.

First generation (1966-1983)

For 1966, GMC ended the use of a shared conventional bus chassis as it debuted its own version derived from its H-Series heavy truck line; Chevrolet debuted its own design in 1967, derived from the C/K medium-duty line. For 1971, both divisions consolidated conventional bus production solely to the C/K chassis.

For 1973, General Motors redesigned the entire C/K truck line, ranging from half-ton pickups to medium-duty trucks. As Chevrolet and GMC had only adopted the C/K chassis together in 1971, GM would continue the production of the 1967-generation chassis for another decade. After 16 years as a Chevrolet and 12 years of production as a GMC, the first-generation C/K bus chassis was retired after 1983.

Chevrolet (1967-1983)

In 1967, Chevrolet moved the medium-duty C/K to a dedicated chassis, taking the school bus chassis with it. As with the previous generation, the design was a rear-hinged "alligator"-design hood. The division offered its conventional school bus chassis with Chevrolet-produced engines, including the 250 inline-6 (replaced by the 292 inline-6), 366 V8, and 427 V8.^[1] In both Chevrolet and GMC school buses, the Allison AT475 3-speed automatic transmission became an option in 1971 with single or two-speed rear axles.^[1]

In 1974, the powertrain lineup was modified, as all GMC-built engines were dropped (alongside all diesel engines).^[1] In 1980, a diesel engine made its return as Detroit Diesel introduced an 8.2L V8.^[1] Dubbed the "Fuel Pincher", it was the first four-stroke engine produced by the company; the engine was available in naturally-aspirated and turbocharged forms.

GMC (1966-1970)

In 1966, the GMC division moved its school bus chassis from the medium-duty C/K to the all new H6500 heavy truck. A forerunner of both the GMC Brigadier and GMC General, the H-series trucks featured an all-steel front fascia with a center-hinged "butterfly" hood for engine access.^[1] Alongside GMC V6 and V8 gasoline engines, GMC school bus chassis were available with Detroit Diesel 6V53 V6 diesels.^[2]

In 1969, GMC transitioned its medium-duty trucks to the Chevrolet-based C/K medium-duty chassis introduced in 1967. The heavy-duty GMC school bus chassis remained in use by the division for 1970, before both divisions consolidated designs for 1971.

Second generation (1984-1991)

For 1984, General Motors released a cowled bus chassis variant of its C/K medium-duty truck line, introduced in 1973. Codenamed B6, the bus chassis was common to both Chevrolet and GMC at the time of its release, differing only in grille design. From the driver's compartment, the B6 chassis shared its steering column and nearly the same instrument panel as its predecessor.

Featuring a tilt-forward fiberglass hood as standard equipment, the B-series was powered by three V8 engines, the 366 and 427 gasoline engines and the Detroit Diesel "Fuel Pincher" diesel. In 1990, the "Fuel Pincher" was discontinued by Detroit Diesel.

In 1985, General Motors developed a modified version of the B-series for Ward Body Works as a chassis for the Ward Patriot school bus. To allow for a shortened hood (to improve driver visiblity), the front chassis of the C/K conventional was shortened for a configuration similar to that of the smaller Chevrolet/GMC P-chassis. The "semi-forward control" design would be developed further by GM with the Thomas Vista, another bus that would use a GM B-series chassis during its production.

Powertrain details
Engine	Configuration	Fuel	Production
Chevrolet Mark IV	366 cu in (6.0 L) OHV 90° 16V V8	Gasoline	1984-1991
Chevrolet Mark IV	427 cu in (7.0 L) OHV 90° 16V V8	Gasoline
Detroit Diesel "Fuel Pincher"	500 cu in (8.2 L) OHV 90° 16V V8 (naturally aspirated, turbocharged)	Diesel

Third generation (1993-2003)

Third generation (1993-2003)
Late 1990s GMC school bus in use in New York.
Overview
Manufacturer	Chevrolet GMC
Also called	Blue Bird CV200 (with body)
Production	1993-2003, built date 92 through 02
Body and chassis
Platform	GM GMT 530 platform
Related	Chevrolet Kodiak/GMC TopKick

For 1990, General Motors introduced its GMT530 medium-duty truck platform as the Chevrolet Kodiak/GMC TopKick, replacing the previous trucks of that nameplate, the GMC Brigadier, and the medium-duty C/K product lines. B-series based on the GMT530 entered production for 1992, as a 93 model year. As with its predecessor, the chassis was shared between Chevrolet and GMC, with only the grille differentiating the two.

The GMT530 B-series was powered by a range of gasoline and diesel engines. As gasoline engines were being phased out of school buses during the 1990s, the B-series became the last full-size school bus to offer them, with a 6.0L (366 cubic inch) V8 as standard. As the Kodiak/TopKick was renamed the C-Series in 1997, the 6.0L V8 was eventually phased out in favor of the Vortec 7.4L V8; the 7.4L V8 was replaced by a 8.1L Vortec V8 (one of the largest gasoline engines ever used in a school bus) in 2001. The Caterpillar 3116 was the first diesel engine option, joined by the turbocharged Caterpillar 3126 in 1997. Along with Allison automatic transmissions, the GMT530 B-series was available with either 5 or 6-speed manual transmissions.

The last manufacturer to offer a gasoline engine in a conventional-chassis school bus (prior to its reintroduction in 2016 in the Blue Bird Vision), a number of GM gasoline school buses were converted to use alternative fuels, including LPG (propane) and CNG (compressed natural gas). When GM replaced the GMT 530 series of medium duty conventionals with the GMT 560 series in 2003, no direct replacement for the B-Series was offered. However, the GMT560 would see use for bus builders with cutaway cab buses in many forms, alongside those based on the Freightliner M2 and Ford F-650 Super Duty.

Blue Bird CV200

Prior to 1992, the B-series chassis was available to any school bus manufacturer. That year, GM and Blue Bird signed a supply and marketing agreement, with the latter company becoming the exclusive supplier of the then-new GMT530 bus chassis for the next 10 years. The resulting model was named the CV200; while the GM B-7 (internal name for the GMT530-based bus chassis) was standard, Navistar International and Ford (later, Freightliner) chassis were available as options.

Along with the 1991 Navistar acquisition of AmTran, the agreement was a part of a series of mergers and acquisitions in the school bus industry between body manufacturers and chassis suppliers, eventually crippling the market share of General Motors as a chassis supplier as the agreement was not renewed. Effectively shut out of the industry as a full-size chassis supplier, General Motors ended chassis production in 2002 (2003 model) to concentrate on cutaway-chassis buses.

Powertrain details
Engine	Configuration	Fuel	Production
Chevrolet Mark IV	366 cu in (6.0 L) OHV 90° 16V V8	Gasoline	Up to 1998
Chevrolet L21 (Vortec 7400)	454 cu in (7.4 L) OHV 90° 16V V8		1998-2001
Chevrolet L18 (Vortec 8100)	496 cu in (8.1 L) OHV 90° 16V V8		2001-2003
Caterpillar 3116	402 cu in (6.6 L) OHV turbocharged inline-6	Diesel	1993-2003
Caterpillar 3126	442 cu in (7.2 L) OHV turbocharged inline-6	Diesel	1997-2003

Usage by body manufacturers

While used nearly exclusively for school bus use, the B-Series chassis was adapted for a wide variety of uses by body manufacturers, ranging from bookmobiles to police buses. In the school bus industry, the General Motors chassis was popular for its wide range of engines. During the 1980s and 1990s, its continued use of gasoline engines remained popular, as the powerplants were sometimes used as the basis for conversion to alternative fuels, including LPG (propane) and CNG (compressed natural gas).

Following the chassis and supply agreement between General Motors and Blue Bird in 1992, the B-series was bodied exclusively by that company, nearly exclusively as a school bus.

Related Research Articles

General Motors Company (GMC), formally the GMC Division of General Motors LLC, is a division of the American automobile manufacturer General Motors (GM) that primarily focuses on trucks and utility vehicles. GMC sells pickup and commercial trucks, buses, vans, military vehicles, and sport utility vehicles marketed worldwide by General Motors. In North America, GMC dealerships are almost always also Buick dealerships, allowing the same dealer to market both upmarket cars and upmarket trucks.

The Chevrolet Silverado, and its mechanically identical cousin the GMC Sierra, are a series of full-size and heavy-duty pickup trucks manufactured by General Motors and introduced in 1998 as the successor to the long-running Chevrolet C/K line. The Silverado name was taken from a trim level previously used on its predecessor, the Chevrolet C/K pickup truck from 1975 through 1998. General Motors continues to offer a GMC-badged variant of the Chevrolet full-size pickup under the GMC Sierra name, first used in 1987 for its variant of the GMT400 platform trucks.

The Chevrolet Express and its mechanically identical twin GMC Savana are full-size vans from General Motors. They replaced the Chevrolet Van and GMC Vandura in 1995. The Express and Savana, were a major upgrade from the previous generation van which dated from the late '60s. The GMT600 featured full body on frame construction, the new central-port injection V6 and V8 engines, and greatly improved ride & handling from its GMT400 derived chassis.

GMT is the designation prefix used for all General Motors truck, sport utility vehicle, and crossover SUV automobile platform applications. This includes both traditional body-on-frame trucks and newer unibody models.

The Thomas Vista is a model line of buses that was manufactured by Thomas Built Buses from 1989 to 1998. Produced nearly exclusively as a school bus, the model line was also sold in commercial-use configurations. To improve forward sightlines for drivers, the chassis of design of the Vista combines elements of conventional buses and transit-style school buses.

General Motors introduced a line of Diesel V8 engine engines for their C/K pickup trucks in 1982. This engine family was produced by GM through 2000, when it was replaced by the new Duramax line. AM General's subsidiary General Engine Products (GEP) still produces a military variant of this engine for the HMMWV.

The Chevrolet Kodiak and GMC TopKick are a range of medium duty trucks that were produced by the Chevrolet and GMC divisions of General Motors from 1980 to 2009. Introduced as a variant of the medium-duty C/K truck line, three generations were produced. Slotted between the C/K trucks and the GMC Brigadier Class 8 conventional, the Kodiak/TopKick were developed as a basis for vocationally-oriented trucks, including cargo haulers, dump trucks, and similar vehicles; on later generations, both cutaway and cowled-chassis variants were produced for bus use.

The medium-duty Ford F-Series is a range of commercial trucks manufactured by Ford since 1948. Derived from the smaller F-Series pickup trucks, the medium-duty range is currently in its eighth generation. Initially slotted between the F-Series pickup trucks and the "Big Job" conventionals, later generations were slotted below the L-Series "Louisville" trucks; during its production, the medium-duty F-Series has been used for an extensive number of applications, competing against the medium-duty Chevrolet/GMC C/K, International S-series, and Freightliner Business Class.

The GMC General are heavy-duty trucks that were assembled by the GMC Truck and Coach Division of General Motors. The largest conventional-cab truck ever produced by GM, the product line was introduced for 1977, replacing the C/M 90/9500 trucks.

The Chevrolet Bruin and GMC Brigadier are heavy-duty trucks that were assembled by the GMC Truck and Coach Division of General Motors. The second generation of the H/J-series heavy-duty conventionals, the Bruin/Brigadier were produced from 1978 to 1988. A short-hood conventional similar to the Ford L-Series and Mack Model R, the Bruin/Brigadier was configured as both a straight truck and a semi-tractor. As a Class 7-8 truck, the product line saw use with short-haul, vocational, and severe-service users.

The Chevrolet Titan and GMC Astro are heavy-duty cabover trucks that were manufactured by the GMC Truck and Coach Division of General Motors. The largest cabover trucks ever produced by GM, the Titan were introduced for 1969, replacing the 1960-1968 GMC "Crackerbox" COEs. The Astro and Titan would become the final trucks of the type assembled and marketed by General Motors, following the 1981 exit of Chevrolet from heavy truck sales and the 1986 creation of the Volvo GM joint venture.

Multi-stop trucks are a type of light-duty and medium-duty truck created for local deliveries to residences and businesses. They are designed to be driven either sitting down or standing up, and often provide easy access between the driver and goods, hence the name "Walk-In Delivery" van. They are taller than full-size vans such as the Ford Econoline, Dodge A-Series/B-Series/Ram Vans, and Chevrolet G-Series vans, but can have wheelbases that are shorter than these models or longer.

The bus chassis variant of the International S series is a cowled bus chassis that was produced by International Harvester from 1979 to 2004. Produced primarily for school bus applications, the chassis was also produced for other applications, including commercial-use buses and cutaway-cab buses. In addition, the cowled chassis formed the basis for front-engine and rear-engine stripped chassis produced for bus applications.

The International 3300 is a cowled (conventional-style) bus chassis manufactured by Navistar International since 2005 for the United States, Canada, and Mexico. While primarily used for yellow school buses, versions of the 3300 are bodied for other applications as well.

The ThomasMinotour is a bus body manufactured by Thomas Built Buses since 1980. The smallest vehicle sold by the company, the Minotour is a bus body designed for cutaway van chassis. Primarily sold for school bus usage, the Minotour is also produced as a MFSAB or in specialized configurations specified by the customer.

The Blue Bird Mini Bird was a Type B school bus built by Blue Bird Corporation, introduced in 1977. It was dropped in the early 2000s as market tastes shifted away from Type B school buses.

The Ford B-series is a bus chassis that was manufactured by the Ford Motor Company. Produced across six generations from 1948 to 1998, the B-series was a variant of the medium-duty Ford F-Series. As a cowled-chassis design, the B-series was a bare chassis aft of the firewall, intended for bodywork from a second-stage manufacturer. While primarily used for school bus applications in the United States and Canada, the chassis was exported worldwide to manufacturers to construct bus bodies for various uses.

GMT K2XX is an assembly code for a vehicle platform architecture developed by General Motors for its line of full-size trucks and large SUVs that started production with the 2014 model year. The "XX" is a place holder for the last two digits of the specific assembly code for each model. The platform, which replaced the GMT900 series that had been in production from 2007 to 2013, was introduced in April 2013 for the 2014 Model Year on the trucks, followed by the December 2013 production on the 2015 large SUVs that debuted in February 2014. The GMT K2XX products are being produced at four GM assembly plants: Arlington, Flint, and Fort Wayne in the United States, along with Silao Assembly in Mexico for the crew cab light duty pickups.

References

1 2 3 4 5 https://www.gmheritagecenter.com/docs/gm-heritage-archive/historical-brochures/GMC/100_YR_GMC_HISTORY_MAR09.pdf
↑ "1966-81 Chevy H/J Series - The 1947 - Present Chevrolet & GMC Truck Message Board Network". 67-72chevytrucks.com. Retrieved 2016-11-23.

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[:0-1] 1 2 3 4 5 https://www.gmheritagecenter.com/docs/gm-heritage-archive/historical-brochures/GMC/100_YR_GMC_HISTORY_MAR09.pdf

[2] "1966-81 Chevy H/J Series - The 1947 - Present Chevrolet & GMC Truck Message Board Network". 67-72chevytrucks.com. Retrieved 2016-11-23.