From the start of Vega production in 1971, Chevy capitalized on the new car’s sporting character by offering a GT option. This package enhanced the Vega’s handling, added a 100-hp engine and provided full instrumentation. By 1974, EPA regs and other factors had reduced the GT to 85 hp.
What the Vega needed was an “image” model that would appeal to high-performance buffs and weekend racers. The result was the Cosworth Vega. Cosworth was the name of a British firm that built racing cars. In August 1973, major car magazines reported that Cosworth would team with Chevy to make 5,000 special ’74 Vegas. These cars wore consecutively numbered dashboard plaques for identification.
But the Cosworth package was much more than a plaque. It included twin camshafts and four valves per cylinder. The cams were hidden below covers with the Chevy bow tie, and the Cosworth and Vega names. They helped to boost performance to 140 hp at 7000 rpm. In fact, the hot 2.0-liter four produced 1.15 hp per cube. The torque rating was 105 ft.-lbs. of torque at 6000 rpm.
There were other upgrades as well. The engine was constructed totally of aluminum and weighed only 305 lbs. The special crankshaft was a hardened, tuftrided, forged unit. All of the con rods were forged, shot peened and magnafluxed. The special forged aluminum pistons had deep-dish tops to provide clearance for the valves. A higher-than-stock 8.5:1 compression ratio was used. The 16-valve cross-flow head differed from Cosworth’s racecar version only in having cast combustion chambers and a different type of valve seat design.
The Cosworth suspension had stiffer springs and shocks and a torque-tube type rear suspension, developed for the Monza, was used. Mag wheels and fat tires set the package off. The cars were done in a distinctive Black finish with gold wheels and gold striping. Interior features included a gold-tone engine-turned dash panel and special instrumentation.
The launch of the Cosworth Vega was delayed by the EPA until after it passed a 50,000-mile emissions test. It finally arrived in March 1975. As a result, on 2,062 of these cars were built during that model year. All of them were constructed on the main line at General Motors Lordstown, Ohio assembly plant. Production supervisors put them together to help assure a high-quality product. With a base price of $5,916, the “Cosworth” had to be of top quality, since a Corvette coupe cost only about $900 more.
Special components of the 1976 Cosworth Vega engine were about the same as those provided in 1975, which is to say that everything was made to special high-performance standards. A computer-controlled induction system was employed, as well as an unusual low-lift cam and special exhausts. A Bendix electronic fuel-injection system was novel at the time.
Changes were also made to the drive train to go along with the engine’s extra potential. Stiffer springs and shocks were used and the roll couple was redistributed to the front. The Monza-type torque-tube rear suspension was used again.
In proper tune, the Cosworth Vega could reach 60 mph in 8.7 seconds and do the quarter-mile in 17.6 seconds at a terminal speed of 80.1 mph. Besides going fast, it looked good. Even the engine compartment had a “designer” look with the cam covers finished in black crackle paint and the model names spelled out in raised letters.
For muscle-car history lovers, the Cosworth Vega has a lot of significance. It started a trend, for domestic car makers, towards modern high-performance sport coupes with double overhead cam four-cylinder engines.