Mecum's event in Kissimmee is, as Penguin said, an auction - not a car show per se. But it's a great place to see a lot of really nice cars going up for auction. To buy at those events, you'll need to know the details in advance of attending. Refer to their web site:
http://www.mecum.com/bidder-registration.cfm
http://www.mecum.com/auctions/auctio...TION_ID=FL0112
https://www.mecum.com/infonet/online...dType=standard
For a vehicle in the price range you're talking, a Buyer's Premium of 6% of the hammer price is also added to the deal.
The lowest priced cars in the '63-'67 model year range will, all things being equal, will be the '64s. '67s and '63s will probably be the most expensive as they're generally the most desirable years.
You'd probably need to attend a specialty car show that is Corvette-focused - I doubt you'll see a Corvette of that vintage at any kind of local show that meets the "low mileage/creampuff/needs no work" condition parameters. Most of those don't get street driven any more........but there are always exceptions!
Bill