The 1975 Monza 2+2 houses then-newly-approved rectangular headlights and a slot-style grille in a slanted nose made of resilient polyurethane. The side window louvers are functional, part of the flow-through ventilation system. The Monza 2+2's two-door hatchback body style is shared with the Oldsmobile Starfire and Buick Skyhawk. The standard engine was the Vega's aluminum-block GM 2300 engine inline-four engine with a single barrel carburetor generating at 4,200 rpm. Optional was the two-barrel carburetor version that generated at 4,400 rpm. Chevrolet's new V8 engine was optional. The smallest V8 ever offered by Chevrolet, it featured a Rochester two-barrel carburetor and generated at 3,600 rpm. For 1975 only, Monzas sold in California and high altitude areas met the stricter emissions requirement by substituting a version of the V8 engine with a two-barrel carburetor tuned to just . The Monza 2+2 and its Buick and Oldsmobile variants feature GM's first use of a torque arm rear suspension, also adopted for the 1975 Cosworth Vega introduced mid-1975, and later, all 1976–1977 Vegas and Pontiac Astres. The basic design was also incorporated into GM's third and fourth generation F-bodies, the Chevrolet Camaro and Pontiac Firebird.