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Though the first two prototype cars to carry the Astro namesake were relatively well known, the third entry in this conceptual saga was somewhat obscure and significantly more bizarre. At the 1969 Chicago Motor Show, Chevrolet unveiled the Astro III which was a gas-turbine prototype that featured a tricycle wheel arrangement.
Power and blinding acceleration were the driving forces behind the development of the 1968-1969 Chevrolet Corvette 427. Only 390 1969 Corvettes were built with the famous L89 427 and while the L89 option was chosen 624 times in 1968, it is still a rare beast relative to total production. The 427 CI engine was good for 435 HP and a strong 460 lb-ft of torque making it one of the best-accelerating cars of its time. 
1969 Baldwin Motion Corvette
Various upgrade packages were offered by Motion Industries, for the Chevrolet models included within the Baldwin Corvette partnership. The most prominent of these packages included the SS (425 HP) and Phase III (500+ HP) offerings. These cars not only came with a performance promise, but a guarantee to back it up. All Phase III cars came with a personal guarantee.
The Manta Ray was actually the 1965 Mako Shark II (XP-830) with a few upgrades, so it featured many of the Mako II's outward features, such as side exhausts and a lower-body (along the rocker panels) silver paint job. The front end had a pointed chin spoiler and the headlights used 2 banks of 3 quartz-halogen lights.
In 1969, Chevrolet changed the perception of Corvette forever by introducing the ultra-powerful ZL-1 Corvette with a 427 CI engine producing 585 horsepower! The 1969 ZL-1 Corvette came equipped with an entirely new big-block engine option that produced more horsepower than any Corvette that had come before it. Any Corvette, when ordered with RPO ZL1, came fitted with an all-aluminum 427 C.I. engine that featured a dry-sump oil system and which weight approximately 100 pounds less.
The L88 was a special option package developed under the direction of Zora Arkus-Duntov, director of GM’s performance division. First introduced in 1967, the L88 Corvette featured a highly modified version of Chevy’s 427-cubic-inch V-8 engine. Although this engine received a factory horsepower rating of 435, actual engine output was somewhere between 540 and 580 horsepower, giving the “stock” L88 enough power to run a quarter-mile in the high-11-second range!