Produced across three generations from 1966 to 2003, the model line was a variant of medium-duty trucks marketed under the Chevrolet and GMC nameplates.

The B-series was constructed as a cowled-chassis design; also known as an incomplete vehicle, all bodywork aft of the firewall was produced by a second-stage manufacturer.

While primarily used for school bus applications, General Motors offered the chassis for multiple commercial and specialty uses.

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.

While General Motors redesigned its entire light and medium-duty C/K truck line for 1973, Chevrolet and GMC retained the previous-generation cowled bus chassis for nearly another decade.

(naturally aspirated, turbocharged) For 1990, General Motors introduced its GMT530 medium-duty truck platform under the Chevrolet Kodiak/GMC TopKick branding.

Alongside conversions of gasoline engines to use LPG (propane), the GMT530 was also offered with options to use CNG (compressed natural gas).

The 1992 supply agreement was among a series of 1990s mergers and acquisitions between body manufacturers and chassis suppliers of school buses.

After failing to renew its supply agreement with Blue Bird in 2002, General Motors was effectively shut out of full-size chassis production, as both body manufacturers competing with Blue Bird were wholly owned by the largest competitors of GM in the medium-duty segment.

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).