Wikipedia describes a Gasser as:

Gassers are based on closed body production models from the 1930s to mid-1960s, which have been stripped of extraneous weight and jacked up using a beam axle or tubular axle to provide better weight distribution on acceleration (beam axles are also lighter than an independent front suspension), though a raised stock front suspension is common as well. Common weight reduction techniques include fiberglass body panels, stripped interiors, and plexiglass windows (sometimes color tinted).

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