was conceived in 1968 to utilize newly developed all-aluminum die-cast engine block technology – the first sand-cast aluminum blocks had preceded the decision to build the car by two years. A relatively large displacement engine with good low-speed torque was decided on, with gear ratios for low engine rpm to achieve fuel economy. Engine testing totaled 6,000,000 miles. A pre-test engine was installed in a Fiat 124 sedan for development of the aluminum block, while several 1968 Opel sedans were used for drive train development Chevrolet instituted a new management program, the car line management technique, to produce the all-new car in two years. The chief vehicle engineer had overall charge of the program. Fifty engineers, dedicated to the design of the entire car, were divided into groups: body, power train, chassis design, product assurance, and pleasability. The latter would check continuously on the vehicles on the assembly line, with computers in another program monitoring quality control of every vehicle built. Fisher Body engineers and draftsmen moved in with the Vega personnel. In October 1968, there was one body style (the "11" style notchback sedan), one engine, one transmission (MB1 Torque-Drive manually shifted two-speed automatic), one base trim level, a bench seat, molded rubber floor covering, no glove box or headliner and no air-conditioning (ventilation was through the upper dash from the wiper plenum). As the market changed, so did the car in development. In December 1968, hatchback, wagon, and panel delivery styles were added; also floor-level ventilation, and an optional performance engine ("L-11" two-barrel) which, predicted as 20% of production, accounted for 75%. Bucket seats were standard. Hatchback and wagon received carpeting and headliners. Optional air conditioning, predicted as 10% of production, was actually selected 45% of the time. In February 1969, Opel three- and four-speed transmissions (three-speed standard, others optional); Powerglide were added (now four transmissions); mechanical fuel pump replaced by in-tank electric pump (making this the first GM product with an in tank fuel pump prior to the adoption of fuel injection); power steering option; base "11" style notchback trim upgraded to match hatchback and wagon carpet and headliner. In April 1969, the car gained gauge-pack cluster, HD suspension, wider tires; adjustable seat back (45% of production); bumpers restyled, lower valance panels added; swing-out quarter window option (10% of production). In July 1969, an electrically heated rear window option (10% of production); "GT" package, $325.00 extra (35%