head, double overhead cams (DOHC), forged components and solid lifters. It produced and . Aluminum engine block GM Research Labs had been working on a sleeveless aluminum block since the late '50s. The incentive was cost. Engineering out the four-cylinder's block liners would save $8 per unit — a substantial amount of money at the time. Reynolds Metal Co. developed a hypereutectic aluminum alloy called A-390, composed of 77 percent aluminum, 17 percent silicon, 4 percent copper, 1 percent iron, and traces of phosphorus, zinc, manganese, and titanium. 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. Basic work had been done under Eudell Jackobson of GM engineering, but final production engineering work was finished by Chevrolet. The Vega engine block was cast in Massena, New York, at the same factory that had produced the Chevrolet Turbo-Air 6 engine for the Corvair. 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 block was cast using the ACCURAD process. The casting process provided a uniform distribution of fine primary silicon particles approximately in size. Pure silicon provides a hard scuff and wear resistant surface, having a rating of 7 on the mohs scale of hardness, the same as quartz, as compared to diamond which is 10. The blocks were aged 8 hours at to achieve dimensional stability. 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. Before being shipped to Tonawanda, the blocks were impregnated with sodium silicate, where they were machined through the outer skin. From Massena, the cast engine blocks were shipped as raw castings to Chevy's Tonawanda Engine plant in Tonawanda, New York. Here they underwent the messy etch and machining operations. The cylinder bores were rough and finish-honed conventionally to a finish then etched by a then-new electro-chemical process. The etching removed approximately of aluminum leaving the pure silicon particles prominent to form the bore surface. With a finished weight of , the block weighs less than the cast-iron block in the Chevy II inline-4. Plating the piston skirts was necessary