General Motors G-Body was a designation for mid-sized rear-wheel drive cars such as Pontiac Grand Prix and Bonneville; Chevrolet Monte Carlo, Malibu, and El Camino; Oldsmobile Cutlass, Buick Regal and GMC Cabellero.
The G-bodies were some of the last cars to follow the classic front-engine, large V-8 and rear-wheel drive muscle car formula and remained popular while other mid-sized cars moved to front-wheel drive vehicles equipped with more modest V8 or V6 engines.
They were also among the last production-based vehicles raced in NASCAR (and quite competitively at that, with the Buick Regal in particular dominating many races in its time). NASCAR regulations continued to stipulate production body parts until 2003 (namely, the hood, roof, and deck lid), but since most of the vehicles that bodies were derived from during this period had a transverse front-wheel drive layout (many even lacking a V8 as an option), the drivetrain and all running gear were either custom-built or sourced from other (usually, older) models.
GM G-BODY