Bore, stroke and valve sizes are identical but it lacks the EA engine's dry sump lubricating system, has a lower compression ratio and different valve timing, and uses Bendix electronic fuel injection instead of Lucas mechanical injection to cope with a wider range of operating conditions as well as emission controls.

[2] In March, 1970 John DeLorean, GM's general manager and vice-president, sent engine designer Calvin Wade to England in search of cylinder head technology to improve the Vega's performance.

Fuel injection would be needed to control emissions without power loss; also stronger internal parts to work with the existing block and the Cosworth head.

At Easter, 1972 GM President Edward Cole drove three Vegas for comparison: a base model, an all-aluminum small-block V8-powered prototype, and the Cosworth.

Approval of development aimed at U.S. Environmental Protection Agency (EPA) certification soon followed, and Wade began a 12-car development program to accumulate test mileage in a range of environments including high altitude, heat and cold, to test the engine's eligibility.

The press was notified of the program and in August 1973 a Car and Driver feature alerted the public to an upcoming 140 hp (100 kW) Cosworth Vega.

The engine needed more dynamometer time, new cam profiles to trade some high-end power for more low-end torque, and a tubular header to replace the cast iron exhaust manifold.

Camshaft lift and duration were eased back and the torque curve reshaped to a street-oriented peak of 5,200 rpm.

One configuration stayed within 1975 California limits, making the Cosworth Vega the only GM car certified for all 50 states.

[3] Cosworth Vega 0001, the original Chicago Auto Show vehicle, with a clear Plexiglas hood, is in the GM Heritage Collection.

[4] All 2,061 1975 Cosworth Vegas were finished in black acrylic lacquer with gold "Cosworth Twin Cam" lettering on the front fenders and rear cove panel and gold pinstriping on hood bulge, body sides, wheel openings, and rear cove.

Included were GT springs, shocks, and stabilizer bars (larger at the rear than the Vega GT's); exclusive BR70-13 BSW radial tires on British-made 6 inch, gold-painted cast aluminum wheels with Chevy center caps; black-finished wiper arms, H.D.

A 1976 facelift included wider grille, tri-color tail lamps and extensive body anti-rust improvements.

[4] Total production of 3,508 cars ended in July 1976 with a Medium Saddle Metallic model delivered to a Cleveland, Ohio dealer.

The Cosworth Vega Twin-Cam engine is a 122 cu in (1,999 cc) inline-four with die-cast aluminum alloy cylinder block and Type 356 aluminum alloy, 16-valve cylinder head with double overhead camshafts (DOHC) held in a removable cam-carrier that doubles as a guide for the valve lifters.

The camshafts, water pump and fan are driven by a fiberglass cord-reinforced neoprene rubber belt, much like the Vega 140 cu in (2,294 cc) engine.

A limited run of 4000 machines, each one built away from the tumult of the assembly line to precision tolerances, as a show of technical force by Chevrolet.

Roll-stiffness distribution is ideal, with little understeer entering a turn, and just the right amount of drift from the tail as you put your foot down to exit .

Road Test magazine, in its 1976 "Supercoupe Shootout"—Alfa vs. Mazda vs. Lancia vs. Saab vs. Cosworth Vega—said: "The results are in Figure 2.