both 2+2 hatchback and notchback body styles, using a modified version of the previous quad rectangular headlamps, now above a full-width open-slot grill. The 2.5 liter (151 CID) inline-four "Iron Duke" was standard for 1978, replacing the Vega's inline-four engine. Engine options were a Buick-designed 3.2 liter (196 CID) V6 engine with a two-barrel carburetor that produced at 3,600 rpm. Replacing the 3.2 liter V6 in California and high-altitude areas was Buick's 3.8 liter (231 CID) V6 engine. Four-cylinder engines and the 3.2 liter V6 were not available in high-altitude areas. The 305 cubic-inch V8 remained optional in all but the "S" hatchback and wagon models. Discontinued at the end of the 1978 model year were the S hatchback, Towne Coupe sport option and the estate version of the wagon. The 1979 Chevrolet Monza lineup was trimmed to four models. Added standard equipment for 1979 included an AM radio, tinted glass, bodyside moldings, and sport steering wheel. Only the 2+2 sport hatchback kept the sloped Euro-look front end; others had a freshened grille. A more-potent standard four-cylinder with a redesigned cross-flow cylinder head and two-barrel carburetor developed 90-horsepower — five more than in 1978. Three optional engines were available: the V6, 231 V6, and 305 V8. The Spyder performance package cost $164 and the Spyder appearance package added $231. All Monzas had a color-keyed instrument panel, and all except the base coupe had a center console, and corrosion protection was improved. Discontinued at the end of the 1979 model year were the Monza wagon, the V6 and the V8. The 1980 model year lineup consisted of a base 2+2 hatchback, notchback, and 2+2 sport hatchback; the 151-cubic-inch (2.5-liter) four-cylinder engine remained standard and the only engine option was the 3.8 liter (231 CID) Buick V6. The wagon was discontinued as the Citation hatchbacks offered equal cubic cargo capacity with the rear seats down along with better rear-passenger accommodation. Chevrolet decided to discontinue the Monza at the end of the 1980 model year although production of 1980 models continued to the end of calendar 1980 with its "1982" Cavalier replacement debuting in early calendar 1981. Monza Spyder The "Spyder" nameplate had been used to designate the 1962–1964 Corvair turbocharged model. The "Spyder" name was introduced for the Chevrolet Monza in 1976. This package included performance equipment and some small appearance items. The Monza Spyder equipment package was available on all 2+2