Mine was a 71 vega - piece of crap. Got it for supposed good gas mileage - would have been far better off with a late 60's mustang with an inline six that was my other choice.
The Cosworth - had to read up on it- very limited production (75 and 76) only 5-6,000 of 'em built - and the engines were waaaaaaaay different than the production models- all hand assembled.
Here's the sickipedia reference on the chevy vega ....
The Vega received praise and awards at its introduction, including 1971 Motor Trend Car of the Year.[1] Subsequently the car became widely known for a range of problems related to its engineering,[2] reliability,[3] safety,[4][5] propensity to rust, and engine durability(mt: absolutely horrible - 50k miles and kiss it goodbye). Despite a series of recalls and design upgrades, the Vega's problems tarnished both its own as well as General Motors' reputation. Production ended with the 1977 model year.
I'd say that was a pretty accurate assessment of the production model vegas. The cosworth's had a whole different engine - designed for racing, and far more durable. GM was trying (and failing) to push their crap production models by showing how good a car the Cosworth was. The public didn't buy the bait and switch. Vegas discontinued in 77.
Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good ...