The Chevrolet G20 was a full-sized van produced by General Motors and for a while became the staple of the North American van fleet.
The G20 and its counterparts replaced the original Chevrolet Corvair Greenbrier Van in the late 60s the model line evolved until it was replaced in 1996 by the Chevrolet Express. 1964-70 G20s came with six-lug wheels (6 lugs - 5.5" (139.6 mm) bolt circle), while the 1971-96 generation came with the 5 lug - 5" (127 mm) bolt circle.
G20s were fitted with the ball joints from the Chevrolet/GMC 3/4 and 1 ton pickups although using the 1/2 ton pickup's brake rotors.
A light duty version, the G10, was produced alongside the G20 - the early versions used the Chevrolet passenger car wheels (5 lugs - 4.75" (120.7 mm) bolt circle) until 1975 (G10s manufactured prior to the 1976 model year had the smaller bolt pattern, common with the short wheelbase vans), yet can still handle LT tire sizes for better handling and stability. The G20 series sported an SB 262 4.3L engine, not much was changed mechanically in the vehicles since their release, other than carburettor to a throttle body fuel system, and less use of a vacuum system. Currently there are more after market part options available for its V8 counterparts. Not much has been done in the lines of performance options for the small V6 G20 models, but the reliability remains the same throughout all the G-series models.
The G20's low cost of upkeep, size, and options have made this van popular with all different kinds of trades, from plumbers to caterers.
Over the years a number of variations have seen production such as the, Chevrolet Beauville (which is the upscale passenger variant), the Chevrolet Sportvan, the 1/2 ton Chevrolet G10, 1 ton and Chevrolet G30 and a chassis version the Chevrolet G31 was produced to support large platforms such as cube vans. In the 1980s, 1-ton chassis versions of the G-Series specifically designed for Class C-Motor Homes were renamed the Chevrolet RV-30. A variation was also produced under the Chevrolet Nomad nameplate, and another model was known as the Chevrolet Bonaventure.
On the GMC side, variations were produced such as the staple GMC Vandura series, and the GMC Rally series such as the Wagon and later the STX, other nameplates offered were the GMC Gypsy, GMC Gaucho, and the GMC MagnaVan the 1 ton GMC Chassis van, which likewise was meant for large platforms.