The engine's cylinder head is cast iron for lower cost, structural integrity and longer camshaft bearing life.

Chevrolet dealers installed a coolant-recovery tank, a low-coolant warning light and extended Vega's engine warranty to 50,000 miles (80,000 km).

Of the Monza's H-body variants, the Pontiac Sunbird adopted Vega's revised Dura-built 140 engine for 1976 only, while the Oldsmobile Starfire offered it 1976-77.

The engine was de-stroked to 3.16 inches (80 mm) giving 2.0 L; 121.7 cu in (1,994 cc), with a 16-valve aluminum cylinder head, double overhead cams (DOHC), forged components and solid lifters.

The A-390 alloy was suitable for faster production diecasting which made the Vega block less expensive to manufacture than other aluminum engines.

Sealed Power Corp. developed special chrome-plated piston rings for the engine that were blunted to prevent scuffing.

Molten aluminum was transported from Reynolds and Alcoa reduction plants to the foundry, inside Thermos-like insulated tank trailers from the factory across the street.

The casting process provided a uniform distribution of fine primary silicon particles approximately 0.001 inches (25 μm) in size.

The technical breakthroughs of the block lay in the precision die-casting method used to produce it, and in the silicon alloying which provided a compatible bore surface without liners.

The etching removed approximately 0.00015-inch (3.8 μm) of aluminum leaving the pure silicon particles prominent to form the bore surface.

Eudell Jackobson of GM engineering pointed out one of the early problems with unexplained scuffing and discovered excessive pressure on the bore hones was causing the silicon to crack.