In 1970, Chevrolet engineers began working closely with a now famous engine
development company in England, Cosworth Engineering Ltd., to design a new European
Formula 2 engine based on GM's innovative aluminum silicon alloy four cylinder block.
In 1971, when it was apparent that the
four valve per cylinder head design was a viable product, word was given by the then
General Manager of Chevrolet, Mr. John Z. Delorean, to develop a Vega
"image" model. This new model would utilize a detuned version of the engine as
well as other high performance/sport options such as 3.73 posi-traction rear axle,
aluminum sport wheels, and full instrumentation.
In later press releases Chevrolet would state; "The Cosworth Vega is a
highly sophisticated sports concept designed to generate excitement and bolster interest
in the GM domestic small car market" It also added "another marketing objective
is to establish the design superiority and engineering excellence of (this) Vega option in
the minds of knowledgeable enthusiasts".
Chevrolet, after a three year development program and a one year delay associated with
a failure to achieve EPA certification in 1974, began building the first of approximately
2,061 1975 1/2 Cosworth Twin Cam Vegas (RPO Z09) in March, 1975.
The unique engines were hand
assembled in a special area at the Tonawanda Engine Plant in New York, tested, and
shipped to the Lordstown, Ohio vehicle assembly facility were Vegas were being built at
rates approaching 100 units per hour.
The Cosworths were assembled on the same line as other Vegas. All
1975 Cosworths were black with
gold striping and gold painted aluminum wheels, each of the vehicles carried a serial
numbered plaque on a gold tinted engine turned dash bezel. The 1975 Cosworth model also
utilized the new Monza torque arm rear suspension (not used on the standard Vega till
1976), special tachometer, and exclusive transmission and final drive gear ratios. The
interior was the same as the GT model custom interior.
In 1976, a five speed transmission with a 4.10 final drive ratio was
added to the option list. A mid model year revision (January 1976) added a sunroof, 8
track tape, and eight additional
colors to the option list.
Unfortunately, even these changes did not help the sagging sales of the Cosworth Vega
and 1976 production ended in July, 1976 with approximately 1446 produced.
Why didn't the Cosworth sell? Most knowledgeable people feel it was a combination of
many factors; high unit costs, (over $6000 dollars in 1976, nearly the cost of a new
Corvette!) less than expected performance, and a general disinterest in the Vega due to
it's previous bad reputation which by 1975 was greatly undeserved.
Now, most surviving Cosworths are owned by people who understand how unique an
automobile it was. The Cosworth Vega included many firsts: the first double
overhead cam sixteen valve engine to be domestically produced and sold by General Motors;
the first use of electronic fuel injection by Chevrolet; the first use of a factory
installed stainless steel exhaust header; the first use of pressure cast aluminum road
wheels.
As many of you know, these items are commonplace on today's vehicles! It was these
firsts that led Car & Driver magazine to name the Cosworth Twin Cam Vega one of worlds
ten best collector cars built since 1974 in their January, 1986 issue. The well
respected magazine Automobile Quarterly completed a significant color photograph story on
the Cosworth Vega in Volume 27-3 issued in September 1989. It appears that this milestone
car is finally getting the respect it rightfully deserves.