<BLOCKQUOTE>quote:</font><HR>Originally posted by CorvetteSS:
In 63 it was just an RPO. Now it is a Corvette model designation that is that GM decided to bring back to pay respect to the Corvette heritage.
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It was a bit more than "just an RPO". "Z" prefix options are used to denote "special equipment packages." These are often special "performance" equipment packages, but may not necessarily have any performance enhancing features.
Back in the early sixties, SCCA rules required a nearly showroom stock configuration for the production classes. RPO Z06 was designed to provide the "heavy duty" features required for racing and was an option to make the Corvette competitive and legal with SCCA.
The original incarnation included a heavy duty drum brake package that featured finned drums, metallic linings, vented backing plates with internal fans, and a dual circuit master cylinder. The package also included a HD suspension that featured double the base spring rates, a larger front anti-roll bar, and specific shocks.
The first version was released only for coupes and included the "quick take-off" (knockoff) wheels and a 36.5 gallon fuel tank that consumed most of the luggage area behind the seats. The knockoffs were never released in '63 due to casting porosity, and a later version of the package released in February unbundled the knockoffs and big tank into separate options, so Z06s are generally segmented into "big tank" and "small tank" groups. With the second release, the Z06 package theoretically became available on convertibles, but none have been absolutely documented, though a couple are claimed.
Ordering Z06 also required the L84 360 HP Fuel Injection engine, M20 four speed transmission, and G81 positration axle in any of six available ratios.
Total '63 Z06 production was 199. Early on it was really not orderable by mere mortals, and the first batch all went to well known racers. There were three or four more batches built as the model year rolled by, and ordinary folks could actually order a Z06 late in the model year.
The RPO code was brought back to honor former Corvette Chief Engineer, the late Zora Arkus Duntov, and its performance certainly makes the new Z06 a deserving descendent of the legendary '63 moniker.
The LS6 engine code was also used before in 1971. The '71 LS6 was an aluminum head 425 HP, 454 CID mechnanical lifter big block. Though it only had a 9:1 compression ratio to comply with GM's edict that all '71 engines operate on low octane unleaded fuel, it was the last true high performance big block every offered as a regular production option.
Sixty-three Zee-zero-six cars are highly sought today by collectors and command values that are only exceeded by the 216 '67 to '69 L-88 models, the two '69 ZL1 cars, and the five Grand Sports.
Duke
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