Overview
Altered is a former National Hot Rod Association (NHRA) drag racing class and a current drag racing chassis configuration that forms the basis of many classes of NHRA Competition Eliminator.
The altered is "[s]ometimes called the poor man's [d]ragster". While the emblematic altered is a short-wheelbase roadster with exposed engine and front frame rails, very similar to the earliest rail dragsters, altereds can be bodied cars also.
By definition, altereds were essentially stock gas, alcohol, or nitromethane-class cars with parts removed or changed, making them ineligible for the previous class, such as Keith Ferrell's Dogcatcher, a 1936 Willys sedan delivery; built as a gasser, Ferrell deliberately left something off to run it in B/Altered.
History
The Altered category originated "for cars with moderate changes", according to the rulebook. It developed from out of the Hot Roadster, Fuel Coupé, and Fuel Sedan categories. In 1956, it was divided in three classes by weight break: A (up to ), B, and C ( and up). Rules allowed moving the engine back up to 25% of the wheelbase, as well as chopping and channeling, which were prohibited in gassers. The class had few limits or requirements. One of the pioneers was Walt's Puffer II, an unsupercharged A/Altered Fiat Topolino powered by a 392 hemi, driven by Walt Knoch.
From Wikipedia (CC BY-SA 4.0).